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[From  the  Kcport  S^j^X^ftW^ of  Agriculture  for  1870.] 


The  External  Parasites  of  Domestic  Animals, 

THEIR  EFFECTS  AND  REMEDIES.* 

BY   A.    E.   YERBILL. 

The  external  parasites  of  our  domestic  animals  nearly  all 
belong  to  the  great  class  of  animals  which  we  call  Insects,  but 
the  internal  parasites  are,  with  few  exceptions,  representatives 
of  the  class  of  Worms.  The  division  of  the  subjects  of  these 
lectures  is,  therefore,  both  convenient  and  natural. 

The  class  of  Insects  includes  a  far  greater  number  of  spe- 
cies than  any  other  class  of  animals,  the  number  actually 
amounting  to  several  hundred  thousands,  each  country  having 
a  vast  number  peculiar  to  itself.  They  are  also  exceedingly 
diverse  in  habits,  as  well  as  in  form  and  structure. 

In  order  to  show  the  affinities  of  the  insect-parasites  and 
their  position  among  other  insects,  it  will  be  necessary  to  give 
a  brief  sketch  of  the  whole  class,  with  a  few  remarks  on  the 
more  important  peculiarities  of  their  anatomy. 

All  insects,  like  the  other  articulated  animals  (worms  and 
Crustacea),  have  a  body  composed  of  a  series  of  segments  or 
rings,  placed  one  behind  the  other,  and  together  forming  a 
sort  of  irregular  tube,  which  incloses  in  one  cavity  all  the  in- 

*  In  the  preparation  of  the  reports  of  these  lectures  on  the  parasites  of  domes- 
tic animals,  we  are  greatly  indebted  to  Dr.  A.  S.  Packard  for  the  use  of  many 
cuts  of  insects  from  his  excellent  "Guide  to  the  Study  of  Insects"  and  the 
"American  Naturalist,"  published  at  Salem,  Mass.;  and  to  Donald  G.  Mitchell, 
Esq.,  editor  of  the  "Hearth  and  Home,"  published  by  Pettingill,  Bates  &  Co.,  New 
York,  for  the  use  of  several  excellent  cuts  of  parasitic  worms,  prepared  to  illus- 
trate a  series  of  articles  on  parasites  of  man  and  domestic  animals  by  the  writer. 
Without  this  assistance  the  lectures  could  have  been  illustrated  only  imperfectly. 
In  addition  to  these  we  have  added,  so  far  as  the  available  funds  would  admit,  fig- 
ures of  the  more  important  parasitic  insects  and  worms,  copied  from  Cuvier,  Gue- 
rin,  Clark,  Leuckart,  Cobbold,  and  others. — A.  E.  Verrill. 


Fig.  2. 


z  BOARD  OF  AGRICULTURE. 

ternal  organs.  The  nervous  system  consists  of 
a  double  nerve-centre  or  ganglion  in  the  upper 
part  of  the  head,  connected  with  another  below 
by  nerves  that  pass  around  the  gullet  on  each 
side,  so  as  to  enclose  it  as  in  a  ring,  and  this 
lower  double  ganglion  is  connected  by  a  double 
nervous  cord  with  a  series  of  similar  ganglions 
or  nerve-masses,  which  are  arranged  along  the 
lower  side  of  the  body,  below  the  intestine,  each 
ganglion  sending  off  small  nerves  to  the  adja- 
cent organs  (figure  2).  The  rings  of  the  body 
are  thickened  in  certain  parts,  and  in  the  head 
and  middle  region  of  the  body  are  more  or  less 
consolidated.  They  thus  form  a  somewhat  firm 
external  skeleton,  composed  of 
a  peculiar  substance,  called 
chitin.  When  the  rings  are 
movable  this  outer  covering, 
where  it  connects  the  rings  to- 
gether, is  thinner  and  flexible, 
and  often  folded  inward  so  as 
to  form  peculiar  joints.  The 
legs,  jaws,  and  other  external 
organs,  are  merely  hollow  out- 
foldings  of  the  outer  covering, 
and  contain,  like  the  body,  the 
muscles  that  move  the  various 
parts,  while  their  cavities  com- 
municate freely  with  that  of 
the  body,  and  thus  receive  their 
supply  of  blood,  nerves,  etc. 
Each  joint  of  the  legs  and  other 
appendages  is  also  formed  by 
a  thinner  portion  of  the  outer 
covering,  which  is  folded  in 
upon  itself  in  various  ways. 
The  wings,  when  present,  are 
also  outfoldings  of  the  integu- 

For  description  of  Figures  see  next  page. 


Fig.  1. 


PARASITES   OP   ANIMALS. 


Fig.  3. 


ment,  which  appear  at  first  in  the  form  of 
little  sacks  containing  fluid,  but  finally  ex- 
pand into  broad  membranes  and  the  sides 
of  the  sack  unite  so  as  to  appear  like  a 
simple  membrane,  supported  by  little 
branching,  hollow  rods,  or  tubes,  which 
communicate  with  the  cavity  of  the  body, 
and  also  form  the  joints  of  the  wings.  The 
legs  and  jaws  originate  from  the  lower  part 
of  the  sides  of  each  ring  that  bears  such 
appendages,  so  that  there  must  be  as  many  rings  or  segments 
in  any  part  of  the  body  as  there  are  pairs  of  such  organs,  but 

Fig.  4. 


FIGURE  1. — "  Hundred-legs,"  ( Scolo^ocryptops  sexspinosa  Say),  natural  size;  color 
deep  orange,  with  yellow  feet.  From  Packard's  Guide. 

FIGURE  2. — Nervous  system  of  Corydalus  cornutas,  a  large  neuropterous  insect; 
a  and  b,  ganglions  of  the  head;  c,  the  three  ganglions  of  the  thorax,  which  send 
nerves  to  the  three  pairs  of  legs ;  d,  d,  the  eight  double  ganglions  of  the  abdomen. 
From  Packard's  Guide,  after  Leidy. 

FIGURE  3. — Portion  of  one  of  the  tracheae  or  breathing  tubes,  prepared  so  as 
to  show  the  spiral  fibre  a,  a  part  of  which  has  been  unwound;  c,  a  secondary 
branch.  From  Packard's  Guide. 

FIGURE  4. — Transverse  section  of  the  thorax  of  a  bee;  a,  one  of  the  nervous 
ganglions ;  6,  breathing  pore  or  spiracle,  opening  into  the  tracheae,  which  branch 
in  the  interior,  and  send  small  tubes  into  the  legs  and  wings;  c,  the  dorsal  vessel 
or  pulsating  organ,  which  circulates  the  blood;  d,  the  intestine.  From  Packard's 
Guide. 


4  BOARD  OF  AGRICULTURE. 

the  wings  originate  from  the  upper  part  of  the  same  rings  that 
bear  legs  below  (fig.  4).  Most  insects  breathe  air  by  means  of 
a  complicated  system  of  finely  branched  air  tubes,  having  a 
sort  of  spiral  spring  to  keep  them  open  (fig.  3),  which  are  con- 
nected with  valvular  openings,  called  spiracles,  along  each  side 
of  the  body.  Some  species  of  spiders  have  respiratory  cavities 
that  somewhat  resemble  lungs,  and  contain  numerous  thin 
membranes,  arranged  like  the  leaves  of  a  book.  These  are, 
however,  connected  with  openings  in  the  lower  side  of  the 
body,  and  may  be  regarded  as  a  peculiar  modification  of  the 
air  tubes  or  tracheae  found  in  other  insects.  In  many  flying 
insects  the  air  tubes  expand  in  certain  parts  into  large  hollow 
vesicles,  which  give  greater  lightness  to  their  bodies.  In  all 
insects  we  can  distinguish  three  regions  of  the  body:  the 
head,  composed  of  several  rings  closely  united  together,  and 
bearing  the  organs  of  the  mouth  and  senses — as  many  pairs 
as  there  are  rings ;  the  thorax,  composed  of  either  three  or 
four  rings,  which  bear  as  many  pairs  of  legs,  and  sometimes 
one  or  two  pairs  of  wings  above ;  the  abdomen,  composed  of 
numerous  rings,  which  are  not  consolidated,  and  generally  bear 
only  the  external  reproductive  organs ;  but  in  the  spiders  they 
bear  the  spinnerets,  in  many  Iarva3  several  pairs  of  fleshy  legs, 
in  centipeds,  etc.,  numerous  legs,  (figures  1  and  6),  and  in 
some  insects  long,  slender,  feeler-like  organs  (figure  5). 

Insects  are  naturally  divided  into  three  great 
groups  or  sub-classes,*  founded  on  important 
differences  in  their  internal  anatomy  and  the 
arrangement  of  their  external  parts. 

I. — HEXAPOD  INSECTS. 

The  highest  sub-class  contains  the  Hexapod 
or  six-legged  insects,  including  all  the  flying 
insects,  and  many  that  are  destitute  of  wings. 
In  these  the  head,  thorax,  and  abdomen,  are 
distinctly  separated  as  three  regions  of  the  body. 

*  According  to  some  writers  these  divisions  are  called  orders. 
FIGURE  5. — "Furniture-bug,"  or  Shiner,  (Lepisma),  natural  size.  A  smooth, 
shining,  neuropterous  insect,  covered  with  minute  silvery  scales,  but  destitute  of 
wings.  It  lives  in  houses  among  books,  papers,  clothing,  or  in  furniture,  etc., 
eating  them  in  various  ways ;  it  is  very  fond  of  the  paste  of  books,  and  will  often 
loosen  wall-paper. 


PARASITES  OP  ANIMALS.  5 

The  head  appears  to  be  composed  of  seven  rings,  and  there 
are  three  pairs  of  mouth  organs.  They  all  breathe  by  means 
of  air  tubes  or  tracheae. 

II. — ARACHNIDS. 

The  next  sub-division,  called  AracJtmda,  includes  the  spi- 
ders, scorpions,  "  daddy-long-legs,"  or  harvest  men,  mites,  etc. 
In  these  the  head  is  generally  more  or  less  united  to,  or  sunken 
in,  the  thorax,  as  in  the  spiders,  which  have  the  abdomen  very 
distinct;  or  the  abdomen  may  be  closely  united  to  the  thorax, 
Fig.  6.  as  in  the  mites  (figure  48).  When  mature  they 
have  eight  legs.  The  head  bears  but  few  organs. 
There  are  no  antennas.  The  eyes  are  simple,  but 
often  numerous.  Many  breathe  by  tracheae,  but 
some  spiders  by  lung-like  organs,  and  others  by 
both  combined. 

III. — MYRIAPODS. 

The  lowest  sub-elass,  called  Myriapoda,  includes 
the  centipeds,  "thousand-legs,"  etc.,  (figures  1 
and  6.)  These  have  the  rings  of  the  thorax  and 
abdomen  all  very  similar,  and  the  rings  of  the  ab- 
domen in  some  become  very  numerous,  sometimes  amounting 
to  several  hundred.  Each  ring  usually  bears  a  pair  of  legs, 
aiid  contains  a  nerve  ganglion.  The  head  is  similar  to  that  of 
the  six-legged  insects,  and  bears  antennae,  and  sometimes  com- 
pound eyes.  They  breathe  by  air  tubes  or  tracheae.  This 
last  sub-class  contains  no  parasites,  but  in  both  the  others 
there  are  numerous  examples.  Yet  in  those  they  are  confined 
to  particular  orders  and  families. 

Among  the  Arachnids  we  find  parasites  only  in  the  lowest 
order,  which  includes  the  mites,  the  true  ticks,  the  itch-insect, 
etc.,  but  among  the  Hexapod  insects  we  find  that  the  parasites 
belong  mostly  to  two  of  the  seven  orders  into  which  they  are 
naturally  divided. 

The  seven  orders  of  six-legged  insects  are  based  on  many 
anatomical  differences,  but  they  are  characterized,  also,  by 

FIGURE  6. — Lithobius  Americanus  Newport,  natural  size;  color  yellowish  brown. 
From  Packard's  Guide. 


6  BOARD   OP  AGRICULTURE. 

differences  in  their  transformations,  and  peculiarities  in  their 
habits.  The  most  obvious  distinctions  are  found  in  the 
structure  of  the  organs  composing  the  mouth,  and  in  the 
wings,  when  these  exist.  Their  names  are  derived  from  the 
character  of  their  wings.  The  orders  are  as  follows  : 

I.  Hymenoptera,  (membrane-winged).    This  order  includes 
the  bees,  wasps,  ichneumon-flies,  saw-flies  (figures  7, 7  a),  etc. 

Fig.  7  a. 
Fig.  7. 


They  have  four  small  but  strong  membranous  wings,  the  front 
pair  largest.  The  body  is  compact,  the  head  large,  and  the 
three  regions  of  the  body  very  distinct.  •  The  head  (figure  8) 
usually  has  three  simple  eyes  Fig.  8. 

in  front,  forming  a  triangle ;  a 
pair  of  slender  antenna3  or 
feelers,  and  a  pair  of  very  large 
compound  eyes  ;  connected 
with  the  mouth  we  find  a  pair 
of  powerful,  often  toothed, 
mandibles  or  jaws;  a  pair  of 
orceps-like  maxillce,  bearing 
near  the  base  a  jointed  palpus 
or  small  feeler  ;  and  finally  the 
labium  or  lower-lip,  which  bears 
a  pair  of  palpi  or  feelers,  and 
the.  ligula  or  tongue,  which  is 
long  and  highly  developed  and 
covered  with  hairs  in  the  bees. 
They  have,  therefore,  all  the 
parts  of  the  mouth  symmetri- 

FIGURE  7.— The  Pear-slug  or  Saw-fly  (Selandria  cerasi  Peck),  enlarged.  Color 
black,  with  white  spots  on  four  anterior  legs  and  feet. 

FIGURE  7a. — Larvae  of  the  same  on  leaf  of  pear,  natural  size ;  and  a,  enlarged. 
It  is  covered  with  sticky  slime.  Both  from  Packard's  Guide. 

FIGURE  8.— Head  of  wild  Bee  (Anthophora),  much  enlarged ;   a,  compound 


PARASITES  OP  ANIMALS. 


cally  developed.  The  jaws  are  used  for  biting  and  cutting  the 
materials  used  in  constructing  their  nests ;  the  maxillae  are 
used  in  manipulating  and  arranging ;  the  tongue  is  used  for 
lapping  up  honey  and  other  liquid  food.  The  Iarva3  are  gen- 
erally soft,  footless,  and  white,  but  those  of  the  saw  flies  re- 
semble caterpillars,  and  have  numerous  abdominal  legs. 

II.  Diptera  (two-winged).     Insects  belonging  to  this  order 
have  but  one  pair  of  wings.     The  three  regions  of  the  body 
are  very  distinct.      The  common  house-fly,  meat-flies,  mos- 
quito, Hessian-fly,  wheat-midge,  onion-fly  (figure  9),  bot-fly, 
Fig.  9.  horse-fly,  and  the  fleas 

are  examples.  The 
mouth  organs- corres- 
pond in  number  with 
those  of  the  Hymen- 
optera,  but  the  mandi- 
bles and  maxillce  are 
usually  formed  like 
long  sharp  lancets,  as 
in  the  horse-fly  (fig. 

10),  or  have  the  shape  of  slender  and 
sharp  piercing  organs,  as  in  the  mosquito. 
The  labium  and  tongue  together  generally 
form  a  long  proboscis,  often  with  the 
tongue  curiously  bilobed  and  expanded  at 
the  end  as  in  the  horse-fly  and  house-fly. 
The  sharp  mandibles  and  maxillaB  are  used 
to  penetrate  the  skin  of  animals,  or  the 
bark  of  plants,  and  rind  of  fruits,  and  the  fleshy  tongue  is 
used  to  suck  up  the  blood  or  other  liquid  food.  The  larvae 

eyes ;  b,  clypeus ;  c,  the  three  simple  eyes  or  ocelli ;  d,  the  antennae ;  e,  labrum  or 
upper  lip  ;.f,  mandibles  ;  h,  maxillary  palpi,  borne  upon  the  base -of  the  maxillae 
i,  which  are  slender  and  hairy ;  j,  labial  palpi ;  k,  ligula  or  tongue ;  /,  palpifer  ; 
m,  paraglossae  or  lateral  lobes  of  the  ligula.  From  Packard's  Guide,  after  New  - 
port. 

FIGURE  9. — Onion-fly  (Anthomyia  ceparum),  considerably  enlarged,  with  larvae, 
a  and  6.  From  Packard's  Guide. 

FIGURE  10. — Head  of  Green-head  fly  or  Horse-fly  (Tabanus  lineola  Fabr.),  much 
enlarged ;  a,  antennae ;  m,  mandibles ;  mx,  maxillae ;  mp,  the  large,  two-jointed 
maxillary  palpi ;  /,  the  ligula  or  tongue ;  lb,  the  labrum.  From  Packard's  Guide. 


Fig.  10. 


8  BOARD    OF  AGRICULTURE. 

are  usually  soft,  white,  and  footless,  and  generally  pass  under 
the  name  of  maggots.  In  this  order  we  find  many  parasites, 
of  which  the  fleas,  sheep-tick,  bat-ticks,  horse-tick,  forest-flies, 
bot-flies,  etc.,  are  examples.  This  order  contains  some  bene- 
ficial and  very  many  injurious  insects. 

III.  Lepidoptera  (scaly  wings).      This  order  includes  the 
butterflies,  moths,  millers,  army  worm  (figure  11),  canker- 
worms,    cut-worms,    silk-worms,    etc. 

The  wings  are  four  in  number,  usually 
broad,  and  covered  with  minute  scales, 
looking  somewhat  like  beautiful  feath- 
ers under  the  microscope,  but  appear- 
ing like  fine  dust  to  the  naked  eye. 
The  mandibles  are  nearly  abortive,  but 
the  maxilla3  are  usually  very  long,  slen- 
der, and  hollowed  out  on  the  inside,  so  that  when  fitted  to- 
gether they  form  a  long  hollow  tube  or  proboscis,  through 
which  they  suck  up  their  liquid  food.  The  proboscis  can  be 
rolled  up  beneath  the  head  when  not  in  use.  The  larvae 
mostly  feed  upon  plants,  and  are  generally  known  as  cater- 
pillars. They  are  often  bright  colored,  sometimes  hairy,  and 
usually  have,  in  addition  to  three  pair  of  small  true  legs,  two 
or  more  pairs  of  fleshy  legs  under  the  abdomen.  Most  of  the 
insects  of  this  order  are  injurious  to  vegetation. 

IV.  Coleoptera  (shield-wings).      Insects  of  this  order  are 
known  as  beetles,  weevils,  etc.      The  front  wings  are  thick- 
ened and  stiff,  not  used  in  flight,  but  serve  to  protect  the 
hinder  wings,  which  are  larger  and  thin,  and  can  be  folded  up 
and  tucked  away  under  them.      The  mandibles  and  maxilla 
are  both  used  as  jaws  for  biting  and  chewing.      The  larvae 
have  usually  three  pair  of  legs,  and  many  are  well  known  as 
grubs  and  borers  in  wood.     The  apple-tree  borer  (figure  12), 
is  an  example.      This  great  order  includes  many  beneficial 
carnivorous  insects,  as  well  as  many  that  are  injurious  to 
vegetation. 

Y.   Hemiptera  (half-wings).      This  order  embraces  those 

FIGURE  11. — Southern  Army-worm  (Leucania)  imago;   and  larva,  a,  natural 
size.    From  Packard's  Guide,  after  Glover. 


PARASITES  OF  ANIMALS. 


9 


insects  properly  called  bugs,  such  as  the  squash-bug  (figure 
13),  strawberry-bug,  bed-bug,  and  also  the  cicada  or  "seven- 
Fig.  12. 


teen-year  locust,"  the  plant-lice,  bark-lice,  cuckoo-spits,  the 
true  lice,  bird-lice,  etc.  In  this  order  we  find,  therefore,  the 
greatest  number  of  external  parasites.  The  wings,  when 
present,  are  often  crossed  upon  the  back,  and  the  front  wings 
are  often  thickened  toward  the  base,  but  in  other  cases,  as  in 
the  cicada  and  plant-lice,  the  wings  are  transparent  and  not 
crossed.  The  mouth  organs  form  a  sharp  hollow  proboscis, 
for  piercing  the  bark  of  plants  or  skin  of  animals,  in  order  to 
suck  up  the  blood  or  sap.  When  not  in  use  the  proboscis  can 
be  folded  down  upon  the  breast,  by  means  of  three  joints. 
The  mandibles  and  maxillae  are  four,  long,  slender,  very 
sharp,  piercing  organs,  often  barbed  near  the  points.  These 
are  enclosed  in  the  jointed  proboscis,  as  in  a  sheath,  but  can 
be  thrust  out  through  the  opening  in  the  end.  The  proboscis 
is  formed  mostly  by  the  lower  lip  or  labium,  but  the  opening 
in  the  upper  side  is  covered  by  the  shorter  upper  lip.  The 
larvae  of  many  Hemiptera  resemble  the  adults  from  the  first, 
except  that  they  lack  wings ;  the  pupae  are  also  active  and 
have  the  same  habits.  They  therefore  undergo  less  remark- 
able transformations  than  those  of  the  preceding  orders. 
Many  of  these  insects  are  beneficial  by  destroying  other  in- 
sects, but  most  are  injurious  to  vegetation  by  sucking  sap. 

FIGURE  12. — Apple-tree  Borer  (Saperda  Candida  Fabr.),  natural  size.  Color 
light  brown  with  two  white  stripes ;  the  lower  figure  represents  the  larvas.  From-, 
Packard's  Guide. 

FIGURE  13. — Squash-bug  ( Coreus  tristis  DeGeer.),  natural  size.  Color  dart 
brown.  From  Packard's  Guide. 

2 


10 


BOARD  OF   AGRICULTURE. 


VI.  Orfhoptera  (straight-wings).     This  order  includes  the 
grasshoppers,  true  locusts,  katydid,  crickets,  cockroaches,  etc. 

Fig.  u.  The   front  wings   are  generally 

long  and  straight,  somewhat 
thickened,  and  in  the  male  often 
have  some  sort  of  musical  ap- 
paratus, as  in  crickets,  katydids, 
etc.  The  hind  wings  are  broad, 
fan  shaped,  and  can  be  folded 
up  like  a  fan  beneath  the  front 
wings,  which  when  folded  gen- 
erally lie  lengthwise  of  the  body, 
forming  a  sort  of  roof. 

The  mandibles  and  maxillae 
are  chewing  organs.  The  larva& 
have  nearly  the  same  form  as  the 
adults,  but  lack  wings ;  they  have 
similar  habits;  the  pupae  are  also  active.  Most  of  these 
insects,  except  the  Mantis,  are  injurious  to  vegetation  by  eat- 
ing the  leaves. 

VII.  Neuroptera  (nerve-winged).     The  dragon-flies,  lace- 
winged  flies  (Figure    15),  May  Kg.  is. 

flies,  Lepisma  (Figure  3),  and 
white  ants,  belong  to  this  order. 
The  wings,  when  present,  are 
thin,  membranous,  and  subdivided  by  very  numerous  rods  or 
nervures  into  small  spaces,  which  are  often  squarish.  The 
mandibles  and  maxilla  are  chewing  organs.  The  abdomen 
is  generally  long.  The  larvae  are  of  many  forms,  often 
aquatic,  generally  carnivorous  and  predacious  in  habits,  and 
usually  undergo  a  complete  metamorphosis  ;  the  pupae  are 
mostly  inactive.  Most  insects  of  this  order,  excepting  the 


Figure  14. — Katydid  ( Cyrtophyllum  concavum  Say),  male,  natural  szie.  Color 
bright  green.  From  Packard's  Guide. 

Figure  15. — The  Lace-wing  Fly  (Chrysopa  oculata  Say),  natural  size,  with  the 
eggs  attached  to  the  tips  of  slender  pedicels.  Body  light  green.  This  insect 
lays  its  eggs  among  plant-lice  (Aphis),  which  the  larvae,  when  hatched,  destroy. 
From  Packard's  Guide. 


PARASITES  OP  ANIMALS.  11 

white  ants  and  Lepisma,  are  beneficial  by  destroying  noxious 
insects. 

To  those  who  desire  more  information  upon  the  struc- 
ture, habits,  and  classification  of  insects  generally,  we  would 
especially  recommend  Packard's  Guide  to  the  Study  of  In- 
sects, Salem,  Mass.,  1869,  and  Harris'  Treatise  on  Insects 
Injurious  to  Vegetation  (illustrated  edition),  Boston,  1862. 

PARASITES  BELONGING  TO  THE  DIPTERA. 

The  Fleas. 

PULICI  D^B. 

It  is  somewhat  singular  that  parasites  are  almost  always 
degraded  species  of  the  orders  and  families  to  which  they 
belong.  This  is  very  evident  in  the  case  of  parasitic  insects, 
for  they  are  mostly  destitute  of  wings,  and  are  imperfectly 
organized  in  other  respects  when  contrasted  with  their  self- 
supporting  allies.  The  fleas  furnish  us  with  examples  of 
degraded  diptera,  and  the  sheep-tick  is  even  more  degraded 
than  the  fleas.  Of  fleas  there  are  several  species  that  attack 
man  and  domestic  animals  ;  but  the  species  do  not  appear  to 
be  so  strictly  limited  to  particular  animals  as  are  the  lice  and 
some  other  parasites ;  for  the  common  dog-flea  and  cat-flea 
will  attack  man  without  hesitation,  and  in  New  England  ap- 
pear to  be  far  more  troublesome  to  the  human  race  than  is 
the  species  commonly  regarded  as  the  real  human  flea  (Pulex 
irritans),  which  so  far  as  I  have  observed,  is  comparatively 
rare,  though  in  some  localities  it  may  be  sufficiently  common, 
as  it  is  in  parts  of  Europe. 

In  the  genus  Pulex,  which  includes  the  common  species  of 
fleas,  the  body  is  compressed  and  the  integument  is  very  firm, 
so  that  they  are  well  adapted  for  gliding  among  hairs  or 
feathers,  and  are  not  liable  to  be  injured  by  any  ordinary 
pressure.  The  wings  are  represented  only  by  two  pairs  of 
short,  stiff  scales,  which  have  little  or  no  power  of  motion. 
The  posterior  legs  are  large  and  powerful,  enabling  them  to 
leap  with  remarkable  agility.  The  head  is  small ;  the  eyes 


12  BOARD   OP  AGRICULTURE. 

are  simple,  in  some  species  very  minute  ;  the  antennae  are  curi- 
ously constructed  with  three  broad,  flat,  singularly  lobed 
joints,  and  are,  in  nearly  all  species,  closely  folded  away  out 
of  sight,  in  a  socket  or  cavity  behind  the  eyes ;  though  in 
the  males  of  the  mouse-flea  and  pigeon-flea  they  are  exposed 
and  carried  erect.  The  mouth  organs  are  peculiarly  con- 
structed and  well  adapted  for  piercing  the  skin  and  sucking 
the  blood.  The  maxillae  (Figure  16,  a),  are  a  pair  of  broad, 
flat,  thin,  somewhat  lance-shaped  organs,  bearing  at  base  the 
long,  four-jointed  feelers  or  palpi  (5).  The  mandibles  (#) 
are  slender,  flattened,  sharp,  piercing  organs,  finely  serrated 
along  their  sides,  like  a  minute  saw.  The  Figure  IG. 

labium  (tT)  is  a  round,  slender,  piercing 
organ,  forming  the  central  lancet.  The 
lower  lip  and  labial  palpi  (<?)  form  to-  a, 
gether  a  sort  of  sheath,  with  a  groove  on 
the  inside,  which  receives  the  mandibles 
and  labium,  when  in  their  natural  posi-  d* 
tion ;  the  labial  palpi  are  four-jointed  in  the  cat  and  dog 
fleas,  if  not  in  all,  though  some  writers  say  they  are  three- 
jointed.  The  mandibles  (c)  and  labium  (d)  form  together 
three  slender  lancets,  and  it  is  by  means  of  these  that  the 
flea  perforates  the  skin.  The  blood  is  then  drawn  up  through 
the  channels  or  spaces  between  these  organs  and  the  labial 
palpi  and  lower  lip,  by  means  of  a  sucking  stomach. 

The  Gat-flea  (Pulex  felis  Bouch4).  Figures  IT,  18. 
This  species  of  flea  is  perhaps  the  best  known  and  most 
common  kind  in  New  England.  It  not  only  infests  nearly  all 
cats  and  the  places  where  they  sleep,  but  is  also  more  or  less 
common  in  dwellings  of  all  classes,  especially  when  cats  are 
allowed  to  roam  about  over  the  carpets.  It  often  becomes 
exceedingly  troublesome  in  sleeping  rooms,  for  it  prefers  to 
spend  the  day  about  the  floor,  in  and  beneath  the  carpet, 
or  in  some  similar  place  of  concealment ;  but  when  oppor- 

Figure  16. — Head  of  the  dog-flea  (Pulex  ranis  Curtis),  highly  magnified;  a, 
the  hroad,  thin  maxillae ;  b,  their  four-jointed  palpi ;  c,  the  mandibles ;  d,  the 
labrum  or  central  seta  of  the  proboscis ;  e,  the  labium  and  labial  palpi.  From 
Duges. 


PARASITES   OP   ANIMALS. 


13 


tunities  offer  it  is  always  ready  to  jump  upon  the  naked  feet 
or  ankles,  and  may  thus  gain  entrance  to  the  bed.  Many 
persons,  especially  ladies  and  children,  are  badly  poisoned  by 

Figure  17.  Figure  18. 


them,  and  may  suffer  severely  for  several  days  from  the  bite 
of  a  single  flea;  for,  unlike  the  mosquito  and  other  blood- 
sucking insects,  they  are  never  satisfied  with  a  single  bite,  or 
with  one  spot,  but  must  travel  about  and  bite  as  they  go, 
literally  "  biting  on  the  run."  In  these  respects,  however,  it 
agrees  closely  with  the  so-called  human  flea  (Pulex  irritans). 

The  cat-flea  (Figure  17)  is  dark  chestnut-brown  in  color, 
and  is  stouter  and  thicker  in  the  thoracic  region  than  Pulex 
irritans,  which  has  a  rather  slender  waist  and  darker  color. 
There  is  a  row  of  sharp  spines  along  the  lower  side  of  the 
head  on  each  side,  and  another  row  of  similar  spines  on  the 
posterior  edge  of  the  first  segment  of  the  thorax;  but  the 
human  flea  lacks  both  these  sets  of  spines.  Other  good  dis- 
tinctions are  found  in  the  joints  of  the  feet  or  tarsi,  and  in 
the  mouth  organs.  In  all  fleas  the  males  and  females  differ 
considerably  in  form  and  size,  the  males  being  smaller  and 
shorter. 

The  female  cat-flea  lays  her  eggs  among  the  fur  of  the  cat, 
to  which  they  are  but  slightly  attached  ;  these  eggs  are  very 
small,  white,  and  long-oval.  As  the  cat  walks  or  runs  about, 
the  eggs  are  constantly  being  scattered  around,  often  in  great 
numbers.  On  one  occasion  I  was  able  to  collect  fully  a  tea- 
spoonful  of  these  eggs  from  the  dress  of  a  lady  in  whose  lap  a 
half-grown  kitten  had  been  held  for  a  short  time.  The  places 


14  BOARD   OF  AGRICULTURE. 

where  cats  sleep  become  well  filled  with  the  eggs.  These 
hatch  in  about  two  weeks  into  little,  white,  footless,  maggot- 
like  larvae  (Figure  18),  which  have  small  tufts  of  hairs  along 
the  sides.  They  are  at  first  about  one-sixteenth  of  an  inch 
long.  The  head  is  pale  yellow,  and  the  posterior  end  of  the 
body  bears  two  spines.  These  larvae  feed  upon  the  decaying 
particles  of  animal  and  vegetable  matter  always  to  be  found 
in  the  dirt  in  which  they  live.  They  move  about  by  means  of 
their  hairs  and  spines.  They  grow  rapidly  in  warm  weather, 
and  in  about  twelve  days,  when  they  mature,  spin  a  slight 
silken  cocoon  and  change  to  a  pupa,  which  is  inactive. 
This  looks  more  like  the  mature  flea  and  has  the  legs  free. 
In  a  short  time,  varying  from  ten  to  sixteen  days  or  more, 
according  to  temperature,  the  pupa  matures,  and  the  full 
formed  flea  comes  forth  from  the  cocoon,  ready  and  willing 
to  take  care  of  itself.  This  it  does  by  leaping  upon  the  first 
living  creature  that  comes  within  range  ;  but  no  doubt  it  is 
better  suited  with  the  cat  than  with  other  animals.  This 
mode  of  increase  and  the  habits  of  the  young  will  explain  the 
reason  why  fleas  are  often  obtained  out  of  doors,  especially  in 
gardens  frequented  by  cats  or  dogs.  Such  fleas  are  often 
called  "  sand-fleas,"  but  they  are  simply  the  progeny  from  eggs 
of  cat  or  dog  fleas  that  have  been  hatched  and  lived  in  the 
dirt  or  soil.  They  pass  the  winter  both  in  the  mature  and 
larval  states,  and  perhaps  also  as  eggs  and  pupae.  There  are 
several  broods  each  season. 

The  Dog-Flea  (Pulex  canis  Curtis).  Figure  19. 
This  species  is  very  similar  to  the  last,  and  is  considered 
the  same  by  several  writers.  It  has  the  same  form  and  color, 
and  the  same  TOWS  of  spines  below  the  sides  of  the  head  and 
on  the  thorax.  But  there  appears  to  be  some  difference  in 
the  mouth  organs.  The  posterior  tarsi  in  this  species  are 

Figure  17.— -Cat-flea  (Pulex  felis  Bouche),  much  enlarged;  a,  the  maxillary 
palpi  arising  from  the  bases  of  the  maxillae,  b ;  c,  the  labial  palpi ;  d,  the  slender 
mandibles.  The  labrum  is  not  shown.  From  Packard's  Guide. 

Figure  18. — Larva  of  Cat-flea  (Pulex  felis  Bouche),  much  enlarged;  a,  one  of 
the  antennae  more  highly  magnified;  6,  posterior  end  of  the  body,  showing  the 
two  spines.  From  Packard's  Guide. 


PARASITES   OF   ANIMALS.  15 

said  to  have  the  fifth  joint  longer  than  Figure  19. 

the  second,  while  in  the  cat-flea  the  second 
is  longer  than  the  fifth.  The  habits  are 
essentially  the  same,  except  that  tins  one 
seems  to  prefer  the  dog's  blood.  It  will 
also  attack  human  beings  when  oppor- 
tunities offer. 

The  Hen-Flea  (Pulex  gallince  Schank)  lives  upon  the  hen 
and  about  poultry-houses  and  yards. 

The  Pigeon-Flea  (Pulex  columboe  Gervais)  lives  upon  do- 
mestic pigeons  and  in  pigeon-houses. 

Other  species  infest  rats,  mice,  bats,  rabbits,  swallows,  and 
various  other  wild  animals  and  birds. 

Remedies  for  Fleas. 

From  the  description  of  the  habits  of  the  larvae  given  above, 
it  is  evident  that  dirt  and  filth  of  all  kinds  afford  facilities  for 
the  increase  of  fleas,  and  that  dogs  and  cats  are  the  means  of 
diffusing  their  own  peculiar  species,  and  also,  no  doubt,  the 
true  human  flea.  The  first  care,  therefore,  should  be  to  see 
that  the  dogs  and  cats,  if  such  are  kept,  are  freed  from  their 
parasites.  To  this  end  they  should  be  made  to  sleep. on  some 
material  like  shavings  or  chips,  that  can  be  easily  burned, 
and  their  sleeping  places  should  be  often  cleaned  and  their 
beds  renewed.  To  remove  the  fleas  themselves  from  the 
animals  a  wash  of  water  containing  6  to  10  per  cent,  of  petro- 
leum, naphtha,  or  benzine,  well  shaken  together,  may  be  used. 
A  weak  solution  of  carbolic  acid  in  water,  about  2  or  3  parts 
of  the  acid  to  100  of  water,  will  also  be  efficacious  for  fleas 
and  other  parasites.  Decoctions  of  tobacco  and  strong  soap 
suds  are  also  recommended. 

When  fleas  are  troublesome  in  dwelling  houses,  a  thorough 
cleaning  of  the  floors  and  an  equally  thorough  beating  and 
cleaning  of  the  carpets,  rugs,  etc.,  will  generally  be  effectual. 
When  cracks  or  crevices  exist  in  the  floors,  a  thorough  wash- 
ing with  the  petroleum,  naphtha,  or  carbolic  acid  water,  will 
be  useful  to  destroy  the  eggs  and  young.  Persian  Insect 

Figure  19. — Head  of  Dog-flea  (Pulex  cants  Curtis),  much  enlarged.  The  parts 
are  the  same  as  in  Figure  16.  From  Duges. 


16  [BOARD  OF    AGRICULTURE. 

Powder,  which  is  a  preparation  from  the  flowers  of  a  plant,  is 
often  used  to  expel  fleas  both  from  carpets  and  the  fur  or 
hair  of  animals.  It  appears  to  be  particularly  obnoxious  to 
them.  But  after  applying  the  powder  to  an  animal  it  should 
soon  after  be  thoroughly  washed  off. 

It  often  happens  that  there  are  really  but  few  fleas,  perhaps 
less  than  a  half  dozen,  in  a  room  that  is  supposed  to  be  over- 
run by  them ;  for  owing  to  their  habit  of  biting  repeatedly,  a 
single  one  may  do  the  mischief  attributed  to  a  large  number. 
In  such  cases  a  careful  search  for  and  capture  of  the  of- 
fenders will  soon  remedy  the  evil.  When  caught,  a  drop  or 
two  of  benzine  will  kill  them  instantly. 

The  Sheep-Tick,  Forest-Flies  or  Horse-Ticks,  etc. 

HlPPOBOSCID-SJ. 

These  are  degraded  Dipterous  parasites,  and  must  not  be 
confounded  with  the  true  ticks,  which  have  eight  legs.  Some 
of  them  are  destitute  of  wings,  like  the  sheep-tick ;  others 
have  long,  narrow,  simple  wings,  like  the  species  infesting  the 
horse,  and  those  of  the  swallow  and  other  birds,  bats,  etc. 
The  body  is  flattened  from  above,  and  is  hard  and  firm,  with 
a  horn-like  or  leathery  texture.  The  head  is  somewhat 
sunken  into  the  front  edge  of  the  thorax,  without  a  distinct 
neck.  The  antennae  or  feelers  are  Tery  small  and  near  to- 
gether. The  eyes  are  large  and  often  occupy  most  of  the 
sides  of  the  head.  The  proboscis  consists  of  two  lateral,  nar- 
row, elongated,  bristly  plates  (regarded  as  maxilla  by  some 
authors),  which  project  in  front  of  the  head.  Below  and 
between  the  bases  of  these  there  is  a  small  orifice  from  which, 
when  about  to  draw  blood,  three,  long,  slender,  piercing 
organs  are  protruded;  but  these  can  be  withdrawn  when  not 
in  use.  These  are  unequal  in  size,  but  equal  in  length.  The 
lower  one,  which  is  largest  and  channeled  along  the  upper 
side  and  dilated  at  base,  receives  the  two  smaller  ones  into 
its  groove.  These  organs  penetrate  deeply  into  the  skin, 
and  through  the  channel  formed  by  the  setae  the  blood  is 
sucked  up. 

They  live  like  lice  among  the  feathers  of  birds  or  hairs  of 


PARASITES   OP  ANIMALS.  17 

animals,  and  run  with  agility  either  forward,  sideways,  or 
backward,  somewhat  like  a  crab.  Their  feet  or  tarsi  are  fur- 
nished with  powerful  denticulated  claws,  with  which  they 
cling  securely.  Their  most  remarkable  peculiarity  is  their 
mode  of  reproduction.  Each  female  produces  but  one  or  two 
young  at  a  time,  but  these  are  born  as  living,  fully  developed 
larvae,  which  are  enclosed  in  a  smooth  oval  skin,  notched  at 
one  end,  within  which  they  change  to  pupae  immediately 
after  birth,  the  enclosing  case  becoming  dark  colored.  The 
female  has  an  uterus-like  enlargement  of  the  oviduct,  in  which 
the  eggs  hatch,  and  this  organ  has  the  power  of  secreting  a 
milk-like  substance  for  the  nourishment  of  the  larvae  until 
full  grown. 

The  Horse-tick  or  Forest-fly  (Hippobosca  equina).   Figure  20. 

This  species  is  almost  as  large  as  the  house-fly,  nearly  black, 
with  conspicuous  yellow  markings  on  the  thorax.     It  some- 
Figure  20"    .  times  infests  the  horse 

to  such  an  extent  as  to 
be  very  troublesome. 
It  attacks  by.  prefer- 
ence those  parts  where 
the  hair  is  thinnest 
and  the  skin  softest, 
especially  under  the 
belly  and  between  the 
hind-logs.  Their  bites 
cause  severe  pain,  and  will  irritate  the  gentlest  horses,  often 
rendering  them  almost  unmanageable,  and  causing  them  to 
kick  dangerously.  When  found  they  cling  so  firmly  as  to  be 
removed  with  some  difficulty,  and  they  are  so  tough  as  not  to 
be  readily  crushed.  If  one  escapes  when  captured,  it  will  in- 
stantly return  to  the  horse,  or  perchance  to  the  head  of  its 
captor,  where  it  is  an  undesirable  guest.  Another  species 
sometimes  infests  the  ox. 


Figure  20.  —  The  Horse-tick   (Eippobosca  equina  Linn.),  enlarged.    From 
Cuvier. 


18  BOARD   OP  AGRICULTURE. 

The  Sheep-tick  (Melophagus  ovinus  Linnaeus).     Figure  21. 

This  insect  never  acquires  wings.  It  has  a  broad  head, 
wider  than  the  thorax.  The  abdomen  is  roundish  and  hairy, 
not  showing  distinct  rings,  and  in  the  gravid  female  becomes 
much  enlarged.  The  legs  are  short  and  stout,  and  the  claws 
very  strong.  The  proboscis  is  as  long  as  the  head.  Like  the 
horse-tick,  it  is  viviparous,  producing  a  full-grown  larva,  en- 
closed in  an  oval  case,  as  shown  in  Figure  21. 

It  is  often  very  troublesome  to  sheep,  especially  lambs. 
There  have  been  numerous  remedies  proposed.  In  general, 
when  there  are  but  few,  they  can  easily  Figure  21. 

be  removed  by  hand  when  the  sheep  are 
sheared  ;  but  when  numerous  on  lambs, 
they  may  be  destroyed  by  various  washes 
or  baths.  Snuff,  or  sulphur  in  powder, 
rubbed  thoroughly  in  to  the  wool,  is  some- 
times used  with  good  results.  A  bath 
made  by  steeping  tobacco  in  water,  about 
2  pounds  to  10  gallons  of  water,  in  which  the  lambs  are 
entirely  immersed,  with  the  exception  of  the  face,  is  said  to 
be  effectual,  but  in  some  cases,  has  proved  injurious  to  the 
health  of  the  lambs.  Probably  the  same  solutions  recom- 
mended for  fleas  would  be  equally  effectual  for  these  ;  but 
the  strength  of  petroleum  water,  or  naphtha  water,  or  car- 
bolic acid  water,  ought  to  be  adapted  to  the  age  and  strength 
of  the  animals  to  which  it  is  applied,  young  lambs  having  a 
much  more  tender  skin  than  dogs  or  old  sheep. 

The  Sot-flies  of  Horses,   Cattle,  and  Sheep. 


The  insects  belonging  to  this  family  are  much  less  degraded 
than  the  other  parasitic  Diptera.  But  in  reality  these  are  not 
parasites,  except  in  the  larval  state.  They  pass  the  pupa  state 
in  the  soil,  and  in  the  winged  state  are  powerful  fliers,  seek- 
ing the  quadrupeds  only  for  the  purpose  of  depositing  their 

Figure  21.  —  Sheep-tick  (Melophagus  ovinus  Linnaeus),  enlarged.  The  figure  on 
the  left  represents  the  puparium  when  first  born.  From  Packard's  Guide. 


'PARASITES  OP  ANIMALS.  19 

eggs.  There  are  numerous  genera  and  species,  each  of  which 
lives,  in  the  larval  state,  upon  some  particular  species  of 
mammalia,  and  usually  in  some  particular  part  of  the  ani- 
mal. In  the  tropical  parts  of  America  there  are  species  which 
live  beneath  the  human  skin,  in  tumors  that  they  cause.  The 
larvas  are  usually  thick,  fleshy  grubs,  destitute  of  feet,  but 
generally  provided  with  rows  of  hooks  or  spines,  by  means  of 
which  they  move  about  in  their  burrows.  The  breathing 
pores  are  in  one  or  two  scaly  plates  at  the  thick  posterior  end 
of  the  body.  In  those  that  are  parasitic  in  the  stomach,  the 
mouth  lias  horny  hooks  by  means  of  which  they  cliii^  to  the 
lining  membrane  ;  but  in  those  that  live  in  tumors  under  the 
skin,  there  are  no  hooks  to  the  mouth,  but  only  fleshy 
tubercles.  They  live  on  the  matter,  or  pus,  which  is  caused 
by  the  irritation  that  they  produce. 

The  flies  generally  have  a  stout,  hairy  body,  sometimes 
looking  somewhat  like  humble-bees.  The  female  has  a  more 
pointed  abdomen,  with  an  extensible  ovipositor.  The  an- 
tenna3  are  very  small,  and  placed  in  little  pits.  The  mouth 
organs  are  almost  abortive,  and  the  mouth  very  small,  for 
these  flies  take  little  or  no  food  in  their  winged  state,  this 
period  of  their  lives  being  wholly  devoted  to  the  reproduction 
of  their  kind.  The  species  that  infest  cattle,  sheep,  and 
horses  have  been  transported  to  nearly  all  parts  of  the  world 
where  these  animals  are  reared ;  but  there  are  many  native 
species  that  are  found  only  in  the  wild  animals.  * 

The  Bot-fly  of  Cattle  (Hypoderma  bovis  Latr).  Figures  22,  23. 
This  fly  is  densely  covered  with  hairs,  except  upon  the 
thorax,  which  is  partially  naked  and  black,  broadly  banded 
with  white  and  yellow.  The  abdomen  is  banded  alternately 
with  yellowish  white  and  black,  and  with  reddish  orange  at 
the  end.  The  front  of  the  head  is  dirty  ashen,  with  yellowish 
white  hairs.  They  appear  from  June  to  September,  and  the 
females  lay  their  eggs  on  the  backs  of  cattle.  According  to 


*  One  species,  Cuterebra  emasculator,  described  by  Fitch,  lives  in  the  scrotum  of 
squirrels,  and  destroys  one  or  both  testicles.  In  some  parts  of  .the  country  it  is 
often  quite  common,  and  doubtless  greatly  diminishes  the  number  of  squirrels. 


20 


BOAED   OF  AGRICULTURE. 


some  writers,  they  pierce  the  skin,  by  means  of  their  peculiar 
gimlet-like  ovipositor ;  but  others  deny  this,  and  say  that  the 
eggs  are  merely  attached  to  the  skin,  and  that  the  young 
larvae,  which  very  soon  hatch,  eat  their  way  in.  At  any  rate 

Figure  22.  Figure  23. 


the  cattle  are  often  greatly  alarmed  by  their  attacks,  and  run 
frantically  about,  sometimes  even  taking  to  the  water  for 
safety,  which  would  hardly  -be  the  case  unless  they  had  suf- 
fered pain  from  their  attacks.  Working  oxen,  when  thus 
attacked,  sometimes  cause  serious  trouble. 

The  larvae  having  entered  the  skin  increase  the  size  and 
depth  of  their  burrows  as  they  grow  larger,  but  always  keep 
up  an  opening  with  the  exterior,  and  keep  the  posterior  end 
of  the  body,  in  which  the  breathing  pores  are  situated,  near 
this  opening  to  get  air.  In  this  way  they  cause,  by  the  irrita- 
tion and  inflammation  that  they  produce,  tumors  or  abscesses 
of  considerable  size  beneath  the  skin,  and  live  upon  the 
matter  formed  by  the  inflammatory  action.  When  young, 
they  are  white,  but  afterwards  become  brownish ;  when  ma- 
ture, deep  brown. 

They  have  transverse  rows  of  minute  hooks ;  the  narrower 
rows  are  on  the  posterior  part  of  each  segment,  and  the  hooks 
point  backward  ;  those  of  the  wider  rows,  point  forward.  These 

Figure  22. — The  Bot-fly  of  Cattle  (Hypoderma  bovis  Latreille),  considerably  en- 
larged. 

Figure  23.— The  full  grown  larva,  enlarged.    Both  from  Packard's  Guide. 


PARASITES   OF   ANIMALS.  21 

hooks  are  used  in  moving  about,  and  no  doubt  cause  consid- 
erable irritation.  The  mouth  is  small  and  inconspicuous, 
with  small  papillae.  •  The  posterior  end  of  the  body  bears  two 
small  plates  in  which  the  spiracles  or  breathing  pores  are 
situated  ;  and  this  end  of  the  body  is  kept  next  to  the  external 
orifice  of  the  tumor.  When  the  larva  is  mature,  which  hap- 
pens from  May  to  July,  it  is  about  an  inch  long  (Figure  23). 
It  then  works  its  way  out  of  the  opening  backward,  and  falls 
to  the  earth,  where,  in  a  day  or  two,  it  changes  to  a  pupa, 
the  dried-up  skin  of  the  larva  serving  as  a  covering  for  the 
pupa.  They  remain  in  the  pupa  state  from  four  to  six  weeks 
during  summer,  when  the  end  of  the  pupa-case  comes  off, 
like  a  lid  or  cap,  and  the  mature  fly  comes  forth.  The  sores 
caused  by  them  heal  very  soon  after  the  larvae  leave. 

Although  these  insects  probably  cause  some  pain,  especially 
at  first,  they  do  not  appear  to  cause  any  permanent  injury, 
and  but  little  inconvenience,  unless  in  large  numbers.  They 
can  usually  be  pressed  out  of  their  burrows  with  the  thumb ; 
but  care  should  be  taken  not  to  crush  or  burst  them  in  the 
burrows.  Or  the  openings  of  the  tumors  may  be  enlarged  with 
a  sharp  knife  or  lancet,  and  then  they  can  be  easily  removed 
and  the  wounds  will  soon  heal.  They  attack  by  preference 
young  and  healthy  or  fat  animals,  perhaps  because  the  skin 
is  softer  and  thinner  in  these.  They  frequent  chiefly  the 
uplands,  and  especially  the  vicinity  of  trees,  and  seem  to 
particularly  avoid  water  or  damp  localities  —  a  fact  that  cattle 
seem  to  learn  by  experience.  Owing  to  this  habit,  cattle  that 
graze  upon  meadows  are  generally  free  from  them,  or  nearly 
so,  although  those  upon  the  neighboring  hills  may  be  at- 
tacked. The  eggs  are  laid  soon  after  the  flies  emerge  from 
the  pupa ;  but  as  there  is  considerable  variation  in  the  time 
when  the  larvae  mature,  the  flies  may  occur  from  June  to 
September.  The  larvae  live  during  the  entire  winter  in  the 
tumors,  and  perhaps  some  of  the  pupae  remain  over  winter. 

The  Sheep  Bot-fly  (CEstrus  ovis  Linn.).     Figure  24. 
This  species  somewhat  resembles  the  preceding  in  form, 
but  is  considerably  smaller,  with  a  rounder  abdomen  in  the 


22  BOARD   OP   AGRICULTURE. 

male,  and  the  color  is  lighter.  The  thorax  is  ash-colored, 
with  four  black  lines  and  small  black  spots.  The  abdomen  is 
light  ash,  more  or  less  spotted  with  blackish.  The  female  has 
a  tapering  abdomen,  with  a  long  ovipositor,  which  is  curved 
forward  when  about  to  deposit  the  eggs. 

The  flies  appear  during  the  whole  summer,  and  according 
to  Mr.  Riley,  deposit  the  young  larvae  previously  hatched  in 
the  oviduct,  on  the  margins  of  the  nostrils  of 
sheep.  u  The  moment  the  fly  touches  this  part  of 
the  sheep,  they  shake  their  heads  and  strike  the 
ground  violently  with  their  fore-feet ;  at  the  same 
time  holding  their  noses  close  to  the  earth,  they 
run  away,  looking  about  them  on  every  side  to 
see  if  the  fly  pursues.  They  also  "  smell  to  the 
grass "  as  they  go,  lest  one  should  be  lying  in 
wait  for  them.  If  they  observe  one,  they  gallop  back,  or  take 
some  other  direction.  As  they  cannot,  like  the  horses,  take 
refuge  in  the  water,  they  have  recourse  to  a  rut  or  dry, 
dusty  road,  or  gravel  pits,  where  they  crowd  close  together 
during  the  heat  of  the  day,  with  their  noses  close  to  the 
ground,  which  renders  it  difficult  for  the  fly  conveniently  to 
get  at  the  nostril."  (Clark,  1796).  This  description,  al- 
though written  long  ago,  applies  equally  well  to  the  habits 
both  of  the  fly  and  sheep,  as  observed  at  the  present  day. 
The  young  larvae  at  once  proceed  to  ascend  into  the  nostrils 
by  means  of  their  hooks  and  writhing  motions,  thus  causing 
great  irritation  and  an  increased  secretion  of  mucus,  upon 
which  they  feed.  They  finally  reach  the  frontal  and  maxil- 
lary sinuses  and  other  cavities,  connected  with  the  nose,  and 
attach  themselves  securely  to  the  mucus  membranes  by  means 
of  the  two  sharp  hooks  upon  their  heads.  They  thus  cause 
great  inflammation,  if  in  considerable  numbers,  and  severe 
illness,  or  even  at  times  convulsions  and  death  result.  This 
disease  is  often  known  as  "  grub  in  the  head  "  among  farm- 
ers. The  disease  is  indicated  by  loss  of  appetite,  frequent 
coughing  or  sneezing,  unusual  discharge  of  matter  from  the 
nose,  slow  and  weak  gait,  dullness,  inability  to  stand,  tossing 

Figure  24. — Larva  of  the  Sheep-bot  ( (Estrus  ovis),  natural  size.    From  Clark. 


PARASITES   OF   ANIMALS.  23 

or  turning  of  the  head,  inclination  to  butt  and  push  with  the 
head,  fits  of  frenzy,  and  general  appearance  of  suffering  and 
weakness,  which  sometimes  goes  so  far  as  to  render  the  animal 
unable  to  rise,  when  death  generally  results.  The  gums,  back 
part  of  mouth,  and  lining  of  the  nasal  cavities  are  often  red  and 
inflamed.  Sometimes  the  larvae  even  force  their  way,  by  the 
openings  through  which  the  nerves  pass,  into  the  brain,  when 
death  quickly  follows. 

These  Iarva3,  when  full  grown  (Figure  24)  are  about  an 
inch  long,  and  have  lost  more  or  less  of  the  white  color  which 
they  had  when  younger,  and  each  ring  is  crossed  above  by  two 
dark  brown  bands ;  there  are  also  small,  round,  raised  brown 
spots  on  the  sides  of  each  segment.  The  small  end,  or  head, 
has  two  sharp  hooks  and  two  papillae ;  but  the  posterior  seg- 
ment bears  two  small  brown  plates,  in  which  the  spiracles 
are  placed,  and  this  segment  can  be  drawn  into  and  con- 
cealed by  the  next,  which  give  a  truncated  appearance  to 
the  posterior  end.  The  under  side  is  flattish,  and  each  seg- 
ment has  a  median  row  of  minute  brown  spines,  which  are 
directed  backward. 

When  full  grown,  they  descend  from  the  nostrils  and  fall 
to  the  earth,  where,  in  the  soil  or  among  the  roots  of  grass, 
they  change  to  pupae  in  about  two  days.  They  remain  in 
this  state  from  six  weeks  to  two  months,  when  a  sort  of  lid  is 
forced  off  from  one  end  of  the  pupae  cases,  and  the  mature 
flies  come  forth,  pair,  and  immediately  proceed  with  the  work 
of  perpetuating  the  race,  for  in  the  winged  state  they  seem  to 
have  no  other  instinct ;  and  not  having  any  mouth,  they  take 
no  food.  When  not  engaged  in  depositing  the  eggs,  they 
seem  sluggish  and  lazy.  The  flies  appear  irregularly  in  June, 
July,  and  August,  and  larvae  of  all  sizes  may  be  found  at  one 
time  in  the  same  sheep.  Each  female  produces  several  hun- 
dreds of  young.  According  to  Mr.  Riley,  *  Over  300  living 
larvae  have  been  taken  from  one  female  fly,  by  Mr.  Cockrill. 

The  amount  of  injury  which  these  insects  do  to  the  sheep 
has  long  been  a  matter  of  discussion  among  veterinary  sur- 
geons and  others ;  but  it  appears  to  be  the  universal  testi- 

*  First  Annual Keport  on  the  Noxious  Insects  of  Missouri,  p.  164,  in  Report  of 
of  Agriculture,  1868. 


24  BOARD   OF  AGRICULTURE. 

mony  of  those  who  are  most  immediately  interested  —  the 
breeders  of  sheep  —  that  their  effects  are  evil,  and  evil  only, 
and  that  the  amount  of  injury  is  in  direct  proportion  to  their 
numbers,  as  is  the  case  with  all  other  parasites.  That,  when 
as  abundant  as  they  often  are,  they  are  capable  of  causing 
death,  seems  to  be  well  established.  As  a  preventive,  it 
has  been  recommended  to  move  the  sheep  to  distant  pastures 
after  most  of  the  grubs  or  larvae  have  left  the  sheep  and  are 
in  the  earth  in  the  pupae  state,  which  happens  during  June  or 
July,  according  to  locality.  In  this  State  probably  the  latter 
half  of  June  would  be  the  best  time  for  this.  Others  smear  the 
noses  of  the  sheep  with  tar,  or  make  them  do  so  themselves 
by  boring  large  augur  holes  in  logs  to  contain  salt,  and  fre- 
quently smearing  the  adjacent  wood  with  tar.  Many  provide 
spots  of  light,  dry  soil  into  which  the  sheep  may  thrust  their 
noses  when  pursued  by  the  fly.  When  the  larva?  have  ac- 
tually entered  the  nostrils  in  large  numbers,  they  may  be 
removed  to  a  considerable  extent  by  a  feather  wet  with  oil  of 
turpentine,  camphor,  or  a  weak  solution  of  carbolic  acid,  or 
of  creosote.  Lime,  in  fine  powder,  is  sometimes  used;  for 
by  sniffing  it,  they  sneeze,  and  thus  expel  the  larvae.  Salt 
water  or  diluted  carbolic  acid  solution  may  also  be  injected 
into  the  nose  with  a  syringe.  It  is  doubtful,  however, 
whether  any  remedies  will  reach  the  larvae  which  have  taken 
up  their  abode  in  the  more  remote  cavities  in  the  bones  of  the 
forehead  and  beneath  the  bases  of  the  horns.  Therefore  it  is 
better  to  apply  these  remedies  early  and  often,  if  necessary. 

Another  species  of  bot-fly  (Hypoderma  lineata  Brauer), 
lays  its  eggs  upon  the  backs  of  sheep  and  cattle,  and  the 
larvae  live  in  tumors  beneath  the  skin,  like  the  more  com- 
mon Hypoderma  bovis  of  cattle.  It  appears  to  be  rare  in  this 
country,  but  has  been  observed  in  Kentucky.  This  fly  may 
be  known  by  three,  longitudinal,  naked,  black  stripes  on  the 
thorax.  The  abdomen  is  very  hairy,  blackish,  with  three 
bands,  the  base  whitish  or  yellowish,  the  middle  black,  the 
apex  orange-red.  The  wings  are  transparent,  somewhat 
brownish,  unspotted.  In  New  Grenada  another  species,  the 
Dermatobia  noxialis  Goud.,  has  the  same  habits,  and  also  at- 


PARASITES    OF   ANIMALS.  25 

tacks  men  in  the  same  way,  forming  painful  tumors  beneath 
the  skin.  The  same  or  a  similar  species  also  infests  the  dogs 
in  the  tropical  parts  of  America. 

Several  peculiar  species  of  Hypoderma  live  beneath  the  skin 
of  the  moose,  elk,  and  other  species  of  the  deer  family.  These 
animals  are  also  infested  by  several  species  of  the  genus 
CepTienomya,  which  live  in  the  larval  state  in  the  throat,  or  at 
the  root  of  the  tongue. 

The  goat  is  attacked  by  a  species  of  Hypoderma,  which 
makes  tumors  under  the  skin,  and  by  a  species  of  (Estrus, 
that  enters  the  frontal  sinuses,  and  has  the  same  habits  as  the 
common  species  of  the  sheep  ;  but  these  two  species  have  not 
been  determined  and  are  little  known.  The  camel  is  infested 
by  the  larvse  of  Cephalomya  maculata  Wd.,  which  lives  in.  the 
nasal  cavities,  like  the  larvae  of  the  sheep-bot.  Even  the  ele- 
phant and  rhinoceros  have  their  peculiar  parasites  of  this 
kind.  The  latter  is  attacked  by  a  bot-fly,  allied  to  that  of  the 
horse,  which  lives  in  the  stomach  in  its  larval  state. 

Bot-fly  of  the  Horse  (Grastrophilus  equi).     Figures  25,  26. 

The  "  bots  "  of  horses  are  the  larvae  of  several  species  of 
flies,  belonging  to  the  genus  called  Gf-astrophilus.  The  largest 
and  most  common  kind  is  Gr.  equi,  the  female  of  which  is 
represented  in  Figure  25.  This  species  is  very  hairy,  and  has 
dark  spots  on  the  wings.  The  eyes  are  black  and  distant ;  the 
top  of  the  head  is  brown,  the  front  whitish  ;  the  thorax  is  brown, 
with  a  darker  brown  or  blackish  central  spot ;  the  abdomen  is 
brown  with  the  transverse  divisions  and  spots  blackish.  The 
male  has  a  rounder  or  broad-oval  abdomen,  which  is  browner. 
This  fly  lays  its  eggs  by  preference  upon  the  hairs  about  the 
knees  of  horses,  especially  on  the  inside  ;  it  also  frequently  at- 
taches them  to  the  hairs  of  the  side  and  back  part  of  the  shoul- 
der, and  occasionally  to  the  tips  of  the  hairs  of  the  mane.  These 
eggs  are  of  considerable  size,  of  a  long  oval  form,  pointed  at 
one  end  and  blunt  at  the  other,  and  adhere  firmly  by  one 
side.  They  may  easily  be  seen  and  can  be  removed  either 
by  thorough  washing  and  brushing,  or  by  cutting  the  hairs 
off  with  scissors.  A  wash  of  carbolic  acid  soap  has  been  re- 
commended to  destroy  them.  Sometimes  500  or  more  may 
4 


26  BOARD   OF  AGRICULTURE. 

be  found  on  one  horse.  In  depositing  the  eggs,  the  female 
fly  hovers  around  the  horse,  and  as  each  egg  is  ready  to  be 
deposited,  she  quickly  advances  and  bends  the  abdomen  for- 
ward, with  the  egg  at  the  end,  and  applies  it  to  the  hair,  to 

Figure  26. 
Figure  25. 


which  it  instantly  adheres  by  the  glutinous  secretion  which 
covers  it.  She  then  retreats  and  prepares  another  egg  Jo r 
the  same  operation.  This  does  not  disturb  the  horse,  unless 
by  a  tickling  sensation,  causing  the  muscles  of  the  skin  to 
contract  with  a  tremulous  motion.  The  eggs  contain  more 
or  less  perfectly  developed  larvae  when  laid ;  and  when  they 
are  mature,  or  have  been  a  few  days  attached  to  the  hair, 
they  burst  open  and  allow  the  young  to  escape  almost  instan- 
taneously, when  moistened.  Thus,  when  the  horse  licks  itself 
or  its  companions,  the  moisture  hatches  the  eggs,  and  the 
young  larvae  are  transferred  to  the  mouth  by  the  tongue  or 
lips,  and  thence  to  the  stomach,  where  they  fasten  themselves 
to  the  lining  membrane  by  their  two  hooks.  They  generally 
occur  in  clusters,  and  are  most  common  in  the  vicinity  of  the 
pylorus,  but  are  found  attached  to  all  parts  of  the  stomach. 
In  this  situation  they  slowly  grow  to  be  large  fleshy  larvae, 
with  a  round  body,  about  an  inch  long  (Figure  25).  The 
segments  of  the  body  are  provided  with  double  rows  of  spines, 
pointing  backward.  These  are  reddish  with  black  tips.  The 


Figure  25.  —  Bot-fly  of  the  horse  ( Gastrophilus  equi  Leach),  female,  natural 
size. 

Figure  26. — Larva  of  the  same,  enlarged.     From  Packard's  Guide. 


PARASITES  OP  ANIMALS.  27 

two  last  segments  do  ftot  show -the  spines,  and  the  posterior 
end  of  the  body  is  rather  truncate,  with  two  fleshy  lobes, 
which  cover,  more  or  less  completely,  a  chitinous  plate,  in 
which  the  spiracles  are  situated.  The  mouth  is  at  the  small 
end,  between  the  hooks,  which  represent  the  maxillae ;  the 
mandibles,  above  and  between  these,  are  small  and  slender. 
At  the  places  where  they  attach  themselves  there  are  found 
small  pits  or  depressions  ;  but  they  do  not  appear  to  cause 
ordinarily  much  irritation  or  inflammation,  unless  in  great 
numbers,  as  they  sometimes  are.  They  have  been  accused  of 
perforating  the  walls  of  the  stomach,  and  this  may  possibly 
be  the  case  in  very  rare  instances ;  but  the  perforations  of 
the  stomach,  so  often  found  in  post-mortem  examinations, 
are  generally  caused  by  the  digestive  action  of  the  gastric 
juice  after  the  death  of  the  animal ;  for  after  death  this  fluid 
will  attack  the  stomach  as  quickly  as  any  other  flesh. 

When  full  grown  they  loosen  their  hold,  and  passing 
through  the  intestine,  fall  to  the  earth.  But  they  often  fix 
themselves  for  a  few  days  upon  the  lining  of  the  intestine, 
and  then  cause  considerable  irritation  and  pain.  Probably 
most  of  the  acute  symptoms  of  "  bots  "  in  horses  are  caused 
in  this  way.  They  often  attach  themselves  in  and  about  the 
anal  orifice,  and  in  that  situation  cause  much  suffering  and 
trouble  to  the  horses,  which  under  these  circumstances,  re- 
fuse to  travel  rapidly,  and  even  after  whipping,  soon  relapse 
into  a  slow  walk,  as  if  lazy.  But  the  bots  can  be  easily  re- 
moved from  this  location,  much  to  the  relief  of  the  horse. 
The  bot-larvge  get  their  growth  and  leave  the  horses  from  the 
latter  part  of  May  to  July,  or  even  later.  They  enter  the 
surface  of  the  soil  and  change  to  pupae  within  the  shrunken 
skins  of  the  larvae.  They  remain  in  the  pupa  state  forty  or 
fifty  days,  and  emerge  in  the  same  way  as  the  preceding  spe- 
cies ;  consequently  the  flies  may  occur  from  the  last  of  June 
till  September,  or  later. 

The  amount  of  injury  caused  by  the  bots  of  horses  has  long 
been  a  matter  of  dispute,  many  writers  claiming  that  they  are 
very  injurious,  and  evert  at  times,  fatal ;  while  others  deny  this, 
and  consider  them  as  harmless,  or  even  beneficial.  This  can 


28  BOARD   OP  AGRICULTURE. 

be  definitely  settled  only  by  experiment;  but  most  reasonable 
men  would  be  content  to  forego  any  possible  benefit,  and  be 
satisfied  with  a  healthy  horse  destitute  of  bots.  No  doubt 
many  diseases  due  to  other  causes  are  commonly  attributed 
to  these  insects,  but  that  they  are  frequently  the  cause  of 
serious  trouble  is  generally  believed  and  admitted.  In  this 
instance  prevention  is  comparatively  easy,  while  all  writers 
admit  that  there  is  no  reliable  cure,  no  mattter  how  much 
they  may  differ  in  other  respects.  The  means  of  prevention 
consist  chiefly  in  frequently  removing  or  destroying  the  eggs, 
as  mentioned  above,  and  also  in  removing  and  destroying  the 
full-grown  Iarva3  when  observed  attached  to  the  rectum.  In 
some  countries  the  grooms  frequently  wash  out  the  mouths 
of  the  horses  with  a  suitable  brush  in  order  to  remove  the 
young  larvae.  Many  drugs  have  been  recommended  to  re- 
move bots  from  the  stomach,  but  none  that  do  not  endanger 
the  life  of  the  horse  can  be  relied  upon ;  and  in  cases  where 
they  bring  away  the  larvae,  it  is  possible  that  those  that  are 
already  in '  the  intestines  are  the  only  ones  affected.  Spirits 
(or  oil)  of  turpentine  is  a  remedy  in  common  use,  but  should 
be  used  with  caution,  if  at  all.  A  better  plan,  under  ordi- 
nary circumstances,  is  to  keep  the  horses  in  good  health  in 
other  respects,  so  that  they  can  the  better  sustain  the  attacks 
of  the  larvae  until  they  naturally  pass  away,  which  will  usually 
take  place  without  serious  injury.  In  exceptional  and  severe 
cases  only,  resort  should  be  had  to  special  medicines  of  a  dan- 
gerous or  doubtful  character  ;  and  then  they  should  be  given, 
if  possible,  in  accordance  with  the  advice  of  a  competent  phy- 
sician. There  are  several  other  species  of  bot-flies  of  the 
horse,  which  are  less  known,  however,  in  this  country. 

The  Gastrophilus  nasalis  is  a  smaller  species,  densely 
hairy,  with  the  thorax  yellowish  red  or  rust-colored.  The 
abdomen  is  either  whitish  at  base,  with  the  middle  black  and 
the  apex  yellowish-brown  and  hairy ;  or  the  base  is  whitish 
and  all  the  rest  brown ;  or  the  middle  is  black,  with  the  base 
and  apex  whitish,  with  grayish  hairs.  The  wings  are  un- 
spotted. The  larvae  are  much  like  tliose  of  the  preceding, 
except  that  they  are  smaller,  and  also  live  in  the  stomach  of 


PARASITES  OF   ANIMALS.  29 

horses.  They  change  to  pupae  beneath  the  manure,  and  the 
flies  appear  from  June  to  September.  It  also  infests  the  ass 
and  mule,  and  some  authors  say  that  it  lives  even  in  cattle. 

The  Gaslrophilus  pecorum  is  densely  covered  with  yellow 
hairs,  with  a  band  of  black  hairs  on  the  thorax  behind  the 
suture,  in  the  male.  The  female  is  yellowish  brown,  the 
abdomen  black,  with  yellowish  hairs  at  its  base,  as  well  as 
on  the  thorax.  The  wings  are  grayish  or  light  brownish, 
clouded  with  yellowish  brown.  The  larvae  are  similar  to 
those  of  the  more  common  G-.  equi,  and  have  similar  habits. 
The  flies  appear  at  the  same  time. 

The  Gastrophilus  hcemorrhoidalis,  or  red-tailed  bot-fly,  is 
a  small  species,  easily  distinguished  by  the  bright  orange-red 
tip  of  the  abdomen.  The  thorax  above  is  olive-gray  and  hairy, 
with  a  black  band  behind  the  suture.  The  base  of  the  abdo- 
men is  whitish  and  the  middle  blackish,  in  strange  contrast- 
with  the  orange-red  of  the  end.  The  larvae  have  the  same 
habits  and  are  found  in  the  same  situations  with  those  of 
the  common  bot-fly,  which  they  much  resemble,  except  that 
they  are  whiter  and  smaller,  their  length  not  exceeding  one- 
half  or  five-eighths  of  an  inch.  They  change  to  pupae  within 
two  days  after  leaving  the  horse,  and  the  pupae  are  deep  red. 
They  remain  in  the  pupa  state  about  two  months,  and  the  flies 
appear  from  the  last  of  June  till  the  cool  weather  of  autumn. 
In  depositing  the  eggs,  the  female  fly  differs  in  habit  from 
the  common  bot-fly,  for  she  selects  the  lips  and  nose  of  the 
horse  as  the  most  suitable  place  for  this  purpose.  In  deposit- 
ing her  eggs  she  therefore  causes  the  horse  much  trouble  and 
uneasiness.  Mr.  Clark  described  the  operation  as  follows : 
"  At  the  sight  of  this  fly  the  horse  appears  much  agitated, 
and  moves  his  head  backwards  and  forwards  in  the  air  to 
baulk  its  touch  and  prevent  its  darting  on  the  lips  ;  but  the 
fly,  waiting  for  a  favorable  opportunity,  continues  to  repeat 
the  operation  from  time  to  time  ;  till  at  length,  finding  this 
mode  of  defence  insufficient,  the  enraged  animal  endeavors 
to  avoid  it  by  galloping  away  to  a  distant  part  of  the  field.  If 
it  still  continues  to  follow  and  tease  him,  his  last  resource  is 
in  the  water,  where  the  (Estrus  is  never  observed  to  follow 


30  BOARD   OP   AGRICULTURE. 

him.  At  other  times,  this  (Estrus  gets  between  the  fore-legs 
of  the  horse  whilst  he  is  grazing,  and  thus  makes  its  attack  on 
the  lower  lip.  The  titillation  occasions  the  horse  to  stamp  vio- 
lently with  his  fore-foot  against  the  ground,  and  often  strike 
with  his  foot,  as  if  aiming  a  blow  at  the  fly.  They  also  some- 
times hide  themselves  in  the  grass,  and  as  the  horse  stoops  to 
graze,  they  dart  on  the  mouth  or  lips,  and  are  always  observed 
to  poise  themselves  during  a  few  seconds  in  the  air,  while  the 
egg  is  preparing  on  the  point  of  the  abdomen."  The  eggs  are 
darker  colored  than  those  of  the  common  bot-fly,  and  contain 
a  nearly  developed  embryo,  so  that  they  very  soon  hatch,  and 
the  young  larvas  are  transferred  to  the  mouth  by  the  tongue, 
and  thence  get  into  the  stomach. 

In  other  countries  there  are  still  other  species  of  bot-flies 
that  infest  the  horse,  ass,  and  mule  ;  among  them  Gast- 
rophilus  inermis  Br.,  which  lives  in  the  horse  ;  6r.  flavipes 
Oliv.,  which  inhabits  the  stomach  of  the  ass  and  mule  ;  and  a 
species  of  Hypoderma,  which  lives  beneath  the  skin  of  all  three. 
But  I  am  not  aware  that  either  of  these  has  been  observed  in 
this  country. 

The  Meat-fly,  Blowflies,  etc.     Figure  27. 

These  flies  are  not  true  parasites,  but  naturally  feed,  while 
in  the  larval  state,  upon  decaying  flesh  and  other  animal 
matter.     Their  larvae  are,  however,  frequently       Fio.  07 
found  in  wounds  and  sores,  both  of  animals 
and  men,  feeding  upon  the  purulent  matter, 
and  when  allowed  to  live  undisturbed,  not  uii- 
unfrequently    attack    the    living    flesh,   when 
their  food  becomes  exhausted  ;  and  in  this  wa, 
if  they  gain  access  to  wounds  in  large  numbers, 
they  will  not  only  greatly  aggravate  and  enlarge 
them,  but  in  many  cases,  when  neglected  for  a 
short  time,  they  have  caused  the  death  of  men 
and  animals  by  actually  eating  away  living  tis- 
sues.    The  females  in  this  group  of  flies  are 
viviparous,  the  eggs   being  retained  in   capa- 

Figure  27.— Larva  or  maggot  of  the  Blue-bottle  fly  (Musca  Ccesar  Linn.),  en- 
larged. From  Packard's  Guide. 


PARASITES   OP   ANIMALS.  81 

cious  spiral  dilations  of  the  oviducts,  until  hatched  into  small 
larvae  or  maggots,  when  they  are  deposited  by  the  mother,  with 
almost  unerring  instinct,  upon  or  near  decaying  flesh.  The 
female  flesh-fly  {Sarcophaga  carnaria  Linn.),  is  said  to  de- 
posit at  least  20,000  of  these  young  larvae.  They  are  ready 
to  commence  feeding  at  once,  and  grow  with  remarkable 
rapidity,  often  becoming  half  an  inch  long  in  two  or  three 
days.  When  mature,  they  crawl  out  of  the  flesh  and  change 
to  long-oval,  brown  pupae,  in  the  earth  or  any  other  conven- 
ient place,  and  the  mature  flies  come  forth  in  a  few  days. 
By  this  rapid  increase  the  progeny  of  a  few  pairs  would  in  a 
short  time  devour  the  carcass  of  a  large  animal.  The  blue- 
bottle fly  {Musca  Ccesar  Linn.),  the  meat-fly  (Musca  vomi- 
toria  Linn.),  and  others  allied  to  them,  are  common  and  well 
known  species,  having  similar  habits.  The  larvae  of  all  these 
are  long,  soft-bodied,  footless  maggots,  smaller  toward  the 
head,  thicker  and  blunt  behind.  The  larva  of  the  blue-bottle 
fly  is  represented  in  Figure  27.  The  eggs  or  larvae  and 
those  of  other  similar  flies  are  not  rarely  swallowed  with 
food  by  men  and  animals,  and  are  capable  of  living,  for  a 
time  at  least,  in  the  stomach  and  intestine,  sometimes  giving 
serious  trouble.  To  keep  them  out  of  wounds  or  sores,  the 
old  females  should  be  kept  away.  If  this  cannot  be  done  by 
bandages,  frequently  washing  the  wounds  with  a  weak  solu- 
tion of  carbolic  acid  will  be  an  effectual  remedy  and  pre- 
ventive. 

PARASITES   BELONGING   TO    THE   HEMIPTERA. 

The  parasitic  Hemiptera  are  all  degraded,  and  mostly 
wingless  forms,  belonging  to  three  very  different  families  : 
the  Cimicidce,  including  the  bed-bug;  Pediculidoe,  including 
the  true  lice  ;  and  the  Mallophagidce,  including  bird-lice,  etc. 


This  family,  as  restricted  by  Westwood,  includes  only  the 
genus  Cimex,  or  the  bed-bug  and  its  allies.  These  have  a 
smoothish,  oval,  flat  body,  with  a  broad  metathorax  ;  a  small 
head  ;  a  slender,  three-jointed  proboscis  or  beak,  which  reaches 
as  far  as  the  front  legs  when  folded  down,  and  slender,  four- 


32  BOARD  OF   AGRICULTURE. 

jointed  antennae,  the  last  joint  not  enlarged  or  clavate.  They 
seldom,  if  ever,  have  wings.  In  addition  to  the  common  bed- 
bug, there  are  species  infesting  pigeons  (<7.  columbarim 
Jenyns)  ;  swallows  (C.  hirundinis  J.)  ;  and  bats  ((7.  pipistrelli 
J.).  It  is  doubtful,  however,  whether  all  these  be  not  identical 
with  the  common  species.  At  any  rate,  it  appears  that  the 
common  bed-bug  will  attach  itself  to  bats  and  various  birds, 
when  opportunities  occur. 

The  Bed-Bug,    (Cimex  lectularius  Linn.).     Figure  28. 

This  species  has  long  been  notorious.  It  was  mentioned 
by  Pliny,  Aristophanes,  Aristotle,  Dioscorides,  and  other  an- 
cient writers.  Yet  English  writers  have  argued  that  it  was 
first  carried  to  that  country  from  America,  and  thence  to 
the  continent  of  Europe.  Moffitt  mentions  it,  however,  as 
having  been  seen  in  England  as  early  as  1503,  though  it  does 
not  appear  to  have  been  common  there  until  a  century  later. 
Its  early  English  name  was  "  wall  louse  "  ;  the  term  "  bug  " 
was  applied  to  it  much  later,  its  original  meaning  having  been 
nearly  synonymous  with  "  bug-bear." 

At  the  present  day  this  insect  is  sufficiently  common 
throughout  the  civilized  world,  if  not  among  the  barbarians 
also.  Its  form  and  general  appearance  are  well  shown  in  Fig- 
ure 28,  which  represents  it  considerably  larger  than  ordinary 
specimens.  Its  size  varies  greatly,  however,  according  to  its 
locality  and  the  amount  of  blood  it  has  been  able  to  imbibe. 
Its  color,  when  young,  is  pale  yellowish,  the  blood  in  the  in- 
testine showing  through;  as  it  grows  older  it  becomes  darker, 
until,  when  full  grown,  it  is  reddish  brown,  the  color  being 
darker  when  filled  with  blood.  The  eyes  are  small  and  bright 
red ;  the  proboscis  is  much  like  that  of  the  ordinary  blood- 
sucking Hemiptera,  which  prey  on  other  insects  ;  the  labium 
forms  a  three-jointed  sheath  or  tube,  the  middle  joint  being 
broadest,  the  last  one  sharply  pointed ;  the  labrum  is  broader 
than  the  basal  joint,  which  it  overlaps.  According  to  Dr. 
Packard,  the  internal  structure  is  as  follows:  "  The  mandibles 
and  maxilla3  arise  near  each  other,  in  the  middle  of  the  head, 
opposite  the  eyes,  their  bases  slightly  diverging.  Thence  they 
converge  to  the  mouth,  over  which  they  meet,  and  beyond  are 


PARASITES   OP   ANIMALS.  33 

free,  being  hollow,  thin  bands  of  chitine,  meeting  like  the 
maxillas,  or  tongue,  of  butterflies,  to  form  a  hollow  tube  for  suc- 
tion. The  mandibles  each  suddenly  end  in  a  curved,  slender 
filament,  which  is  probably  used  as  a  tactile  organ  to  explore 
the  best  sites  in  the  flesh  of  their  victim  for 
Figure  28.  ^  drawing  blood.  On  the  other  hand,  the 
maxilla3,  which  are  much  narrower  than  the 
mandibles,  become  rounded  toward  the  end, 
bristle-like,  and  tipped  with  numerous  ex- 
'ceedingly  fine  barbs,  by  which  the  bug 
anchors  itself  in  the  flesh,  while  the  blood  is 
pumped  through  the  mandibles.  The  base 
of  the  large,  tubular  labium,  or  beak,  which  ensheathes  the 
mandibles  and  maxilla?,  is  opposite  the  end  of  the  clypeus,  or 
front  edge  of  the  upper  side  of  the  head,  and  at  a  distance 
beyond  the  mouth  equal  to  the  breadth  of  the  labium  itself. 
The  labium,  which  is  divided  into  three  joints,  becomes  flat- 
tened toward  the  tip,  which  is  square,  and  ends  in  two  thin 
membranous  lobes,  probably  endowed  with  a  slight  sense  of 
touch."  At  the  same  time  that  the  blood  is  sucked  up,  some 
poisonous  secretion  or  saliva  is  introduced  into  the  wound, 
perhaps  to  render  the  blood  more  liquid.  To  some  persons 
these  bites  are  extremely  poisonous  and  cause  large  inflamed 
swellings  and  violent  itching,  while  in  other  persons  no  such 
effects  occur,  and  the  bites  are  scarcely  noticed. 

These  insects  are  inclined  to  be  gregarious  in  their  habits, 
and  are  fond  of  herding  together,  a  dozen  or  more  in  aplace, 
whether  in  a  crack,  knot-hole,  chink  in  the  walls  of  houses,  or 
any  snug  corners  about  a  bedstead.  They  are  also  fond  of 
returning  constantly  to  the  same  hiding-place,  morning  after 
morning,  after  their  nocturnal  raids,  just  as  many  birds  re- 
turn regularly  to  their  roosts.  On  this  account  their  retreats 
become  discolored  by  dark  spots  of  excrement.  When 
much  disturbed,  or  when  food  fails,  they  will  disperse,  how- 
ever, and  each  one  will  migrate  on  its  own  account.  In  the 
night  they  are  quite  lively  and  nimble,  and  run  about  with 

Figure  28. — Bed-bug  (Cimex  leetularius  Linn.),  enlarged.  The  straight  line 
shows  the  ordinary  length.  From  Packard's  Guide. 

5 


34  BOARD   OP   AGRICULTURE. 

great  rapidity,  and  can  then  evidently  see  better  than  by  day. 
They  are  capable  of  making  long  journeys  even  during  the  day? 
and  may  thus  migrate  from  house  to  house.  They  are,  how- 
ever, not  restricted  to  human  dwellings  or  to  human  blood, 
for  they  often  take  up  their  residences  in  poultry  houses  and 
yards,  at  times  completely  swarming  in  such,  places.  They 
will  also  attack  dogs  and  cats,  and  may  live  about  the  places 
where  those  animals  sleep.  They  have  even  been  found  in 
the  woods  under  the  bark  of  dead  trees.  The  same  species, 
apparently,  also  attacks  bats,  and  may  thus  enter  houses.  In 
fact,  there  are  a  great  many  ways  in  which  they  may  get  into 
the  best  of  houses,  besides  the  well  known  method  of  adhering 
to  clothing,  etc.  It  is,  therefore,  no  disgrace  to  any  house- 
keeper that  a  bug  should  now  and  then  be  detected  in  the 
house  ;  but  the  disgrace  consists  in  allowing  them  to  remain 
undisturbed  until  their  numbers  increase  to  a  great  extent,  as 
they  will  most  surely  do  if  neglected.  Many  kinds  of  Hem- 
iptera,  like  the  squash-bug,  etc.,  have  the  power  of  forming  a 
peculiar  odorous  secretion,  which,  from  the  similarity  of  the 
odor,  probably  consists  in  part  of  formate  of  amylic  ether ; 
but  in  the  bed-bug  this  odor  is  combined  with  others  that 
are  far  more  disagreeable. 

The  eggs  are  long-oval  and  white,  and  are  laid  in  clusters 
in  the  cracks,  etc.,  about  bedsteads  and  other  places  that  they 
frequent.  The  young  hatch  by  forcing  off  one  end  of  the  egg- 
shell like  a  lid.  The  young,  when  first  hatched,  are  whitish 
and  translucent,  and  although  having  three  legs  and  the  gen- 
eral features  and  habits  of  the  old  ones,  they  differ  considerably 
in  form,  being  more  louse-shaped.  They  have  a  broader  and 
more  triangular  head,  and  shorter  and  thicker  antenna. 
They  cast  their  skins  several  times  during  growth,  each  time 
looking  a  little  more  like  the  adult  than  before.  It  is  said 
that  they  require  eleven  weeks  to -mature,  but  this  probably 
differs  according  to  the  temperature  and  food.  They  are, 
however,  lively  and  blood-thirsty  from  the  first,  and  are  well 
able  to  look  out  for  themselves.  Their  skill  in  finding  a 
sleeping  person  and  reaching  him  is  marvelous  indeed. 

In  ordinary  cases  there  is  no  great  difficulty  in  eradicating 


PARASITES  OF   ANIMA.LS  35 

these  insects  completely,  if  a  proper  amount  of  care  is  be- 
stowed in  the  way  of  keeping  the  house  and  beds  clean  and 
neat.  The  principal  trouble  arises  from  neglect  on  the  part 
of  housekeepers  to  examine  the  beds  frequently,  for,  as  al- 
ready intimated,  no  bed  is  sure  to  escape  their  attentions  for 
any  great  length  of  time,  especially  in  cities,  where  they  may 
at  any  time  walk  in  from  some  neighbor's  house  for  a  friendly 
visit  or  morning  call. 

When  they  are  merely  located  in  bedsteads,  or  bedding,  there 
is  no  better  way  than  to  make  a  careful  and  thorough  examina- 
tion of  all  cracks  and  corners,  and  when  any  are  seen,  a  little 
benzine  poured  upon  them  will  kill  them  instantly,  and  the 
benzine  should  be  poured  into  all  suspicious  cracks,  which 
cannot  otherwise  be  reached.  Scalding  hot  water  thoroughly 
applied  is  also  effectual,  but  is  liable  to  injure  the  varnish  of 
furniture.  One  examination  of  a  bed  is  seldom  sufficient,  for 
eggs  that  have  escaped  observation,  may  subsequently  hatch. 
Therefore  two  or  three  searches,  with  benzine  in  hand,  should 
be  made  at  intervals  of  a  week  or  ten  days.  The  use  of  cor- 
rosive sublimate  and  similar  poisons  is  unnecessary  and 
objectionable,  for  such  preparations  are  not  more  dangerous 
to  the  bugs  than  to  the  persons  who  occupy  the  beds,  and  are 
less  fatal,  even  when  applied  directly  to  the  bugs,  than  ben- 
zine. When  the  bugs  have  also  taken  up  their  residence  in 
the  cracks  and  crevices  in-the  walls  of  old  houses,  it  is  much 
more  difficult  to  destroy  them.  If  very  bad,  the  house,  when 
empty,  may  receive  a  thorough  fumigation  with  burning  sul- 
phur, which  will  generally  prove  very  effectual.  Hen-houses 
and  other  out-buildings  may  be  thoroughly  drenched  with  a 
mixture  of  crude  petroleum  and  water,  or  with  the  solution 
of  carbolic  acid. 

Bed-bugs  are  extremely  tenacious  of  life  and  have  wonder- 
ful powers  of  fasting.  They  have  been  kept  hermetically 
sealed  in  glass  bottles  for  more  than  a  year  without  any  food, 
and  were  still  lively  and  had  a  good  appetite. 

PEDICULID^. 

This  family  includes  the  ordinary  lice  of  man  and  quadru^ 
peds,  which  are  furnished  with  a  sucking  mouth.  They  are 


36 


BOARD  OP  AGRICULTURE. 


Figure  29. 


very  low,  degraded  Hemiptera,  destitute  of  wings.  The  head 
is  small,  conical,  and  narrow ;  the  thorax  is  small  and  in- 
distinctly separated  into  segments  ;  the 
abdomen  is  large,  flattish,  rounded  or 
oval,  with  nine  segments.  The  antenna 
are  very  slender  and  five-jointed.  The 
eyes  are  simple  and  very  minute.  The 
feet,  or  tarsi,  have  two  joints,  the 
last  joint  forming  a  strong  hook  for 
grasping  the  hairs  firmly  while  crawling 
and  climbing  among  it.  The  mouth- 
parts  form  a  long  and  extremely  slender 
fleshy  tube,  which  is  retracted  when  not 
in  use,  and  is  capable  of  being  intro- 
duced into  the  skin,  for  the  purpose  of 
sucking  blood.  The  structure  of  the 
mouth  is  as  follows,  according  to 
Schiodte :  u  The  peculiar  attenuation  of 
the  head  in  front  of  the  antennae  at  once 
suggests  to  the  practised  eye  the  exist- 
ence of  a  mouth  adapted  for  suction. 
This  mouth  differs  from  that  of  Rhyn- 
chota  [Hemiptera,  bed-bug,  etc.]  gen- 
erally, in  the  circumstance  that  the 
labium  is  capable  of  being  retracted  into 
the  upper  part  of  the  head,  which  there- 
fore presents  a  little  fold,  which  is  ex- 
tended when  the  labium  is  protruded. 
In  order  to  strengthen  this  part,  a  flat 
band  of  chitine  is  placed  on  the  under 
surface,  just  as  the  shoemaker  puts  a 

Figure  29.— Proboscis  of  body-louse  (Pediculus  corporis  DeG6er),  entirely  pro- 
truded and  seen  from  above,  magnified  one  hundred  and  sixty  times ;  aa,  the 
summit  of  the  head,  with  four  bristles  on  each  side  ;  bb,  the  chitinous  band,  and 
c,  the  hind  part  of  the  lower  lip— such  as  they  appear  through  the  skin  by  strong 
transmitted  light;  dd,  the  foremost  protruding  part  of  the  lower  lip  (the  haus- 
tellum);  ee,  the  hooks  turned  outwards ;  /,  the  inner  tube  of  suction,  slightly 
bent  and  twisted ;  the  two  pairs  of  jaws  are  perceived  on  the  outside  as  thin 
lines ;  a  few  blood  globules  are  seen  in  the  interior  of  the  tube.— From  American 
Naturalist. 


PARASITES  OF   ANIMALS.  37 

small  piece  of  gutta-percha  into  the  back  of  an  India-rubber 
shoe  ;  as,  however,  the  chitine  is  not  very  elastic,  this  band  is 
rather  thinner  in  the  middle,  in  order  that  it  may  bend  and 
fold  a  little  when  the  skin  is  not  extended  by  the  lower  lip. 
The  latter  consists,  as  usual,  of  two  hard  lateral  pieces,  of 
which  the  fore  ends  are  united  by  a  membrane  so  that  they 
form  a  tube,  of  which  the  interior  covering  is  a  continuation 
of  the  elastic  membrane  in  the  top  of  the  head ;  inside  its 
orifice  there  are  a  number  of  small  hooks,  which  assume 
different  positions  according  to  the  degree  of  protrusion  ;  if 
this  is  at  its  highest  point  the  orifice  is  turned  inside  out,  like 
a  collar,  whereby  the  small  hooks  are  directed  backward,  so 
that  they  can  serve  as  barbs.  These  are  the  movements 
which  the  animal  executes  after  having  first  inserted  the 
labium  through  a  sweat-pore.  When  the  hooks  have  got  a 
firm  hold,  the  first  pair  of  setae  (the  real  mandibles  trans- 
formed) are  protruded ;  these  are,  towards  their  points,  united 
by  a  membrane  so  as  to  form  a  closed  tube,  from  which, 
again,  is  exserted  the  second  pair  of  setae,  or  maxillae,  which 
in  the  same  manner  are  transformed  into  a  tube  ending  in 
four  small  lobes  placed  crosswise.  It  follows  that  when  the 
whole  instrument  is  exserted.  we  perceive  a  long  membranous 
flexible  tube  hanging  down  from  the  labium,  and  along  the 
walls  of  this  tube  the  setiform  mandibles  and  maxillae  in  the 
shape  of  long  narrow  bands  of  chitine.  In  this  way  the  tube 
of  suction  can  be  made  longer  or  shorter  as  required,  and 
easily  adjusted  to  the  thickness  of  the  skin  in  the  particular 
place  where  the  animal  is  sucking,  whereby  access  to  the 
capillary  system  is  secured  at  any  part  of  the  body.  It  is 
apparent,  from  the  whole  structure  of  the  instrument,  that  it 
is  by  no  means  calculated  for  being  used  as  a  sting,  but  is 
rather  to  be  compared  to  a  delicate  elastic  probe,  in  the  use  of 
which  the  terminal  lobes  probably  serve  as  feelers.  As  soon 
as  the  capillary  system  is  reached,  the  blood  will  at  once 
ascend  into  the  narrow  tube,  after  which  the  current  is  con- 
tinued with  increasing  rapidity  by  means  of  the  pulsation  of 
the  pumping  ventricle  and  the  powerful  peristaltic  movement 
of  the  digestive  tube." 


38  BOARD   OP  AGRICULTURE. 

The  various  species  of  these  lice  have  similar  habits,  and  all  are 
blood  suckers,  but  each  species  inhabits  only  certain  kinds  of 
animals,  and  some  are  restricted  to  particular  parts  of  the 
skin.  Many  animals  have  two  or  more  species  of  these  para- 
sites. Five  species  have  been  described  as  parasitic  upon  man, 
though  but  three  are  common. 

When  they  become  very  abundant,  as  they  soon  will  if  the 
animals  upon  which  they  once  get  well  established  be  neg- 
lected, they  cause  great  irritation  of  the  skin  and  nervous 
system,  and  the  itching  that  they  produce  causes  the  animals 
to  rub  themselves  against  buildings,  fences,  etc.,  and  thus  the 
hair  is  often  worn  off  and  the  skin  abraded.  Such  animals 
generally  soon  become  weak  and  emaciated,  and  are,  there- 
fore, more  liable  to  be  attacked  by  other  diseases.  • 

There  are  various  washes  which,  if  properly  applied,  will 
very  rapidly  destroy  all  species  of  lice,  without  much  trouble. 
The  use  of  preparations  of  mercury  and  arsenic,  and  all  similar 
poisons,  should  be  avoided,  for  they  often  poison  the  animals, 
as  well  as  the  persons  who  use  them,  and  thus  the  remedy 
may  be  worse  than  the  disease. 

A  strong  solution  of  tobacco,  made  by  boiling  cheap  tobacco 
in  water,  is  an  effectual  remedy,  in  common  use.  Snuff 
rubbed  into  the  hair  is  also  used.  Ordinary  whale-oil,  such  as 
was  formerly  used  in  lamps,  poured  upon  the  skin  along  the 
back  of  an  ox,  cow,  calf,  or  sheep,  will  diffuse  itself  over  the 
skin  and  kill  the  lice.  Weak  petroleum  water,  or  carbolic 
acid  solution,  or  carbolic  soap,  may  be  used  as  a  wash,  or 
small  animals  may  be  immersed  in  a  bath,  taking  care  to 
keep  the  nose,  mouth,  and  eyes  out  of  it.  But  perhaps  one  of 
the  best  and  simplest,  as  well  as  safest,  washes  for  this  pur- 
pose, as  well  as  to  destroy  fleas,  mites,  itch-insects,  mange- 
acari,  and  all  other  external  parasites  of  man  and  animals,  is 
a  solution  of  sulphuret  of  potassium  in  water, — two  to  four 
ounces  to  the  gallon  of  cold  water,  varying  the  strength  ac- 
cording to  the  age  and  tenderness  of  the  skin  of  the  animal, 
for  the  solution  will  contain  some  free  potash,  which,  if  too 
strong,  might  irritate  a  delicate  skin.  There  is  otherwise  no 
danger  from  its  use,  though  its  odor,  like  sulphuretted  hydro- 


PARASITES  OF  ANIMALS.  39 

gen,  is  disagreeable,  and  it  should  be  used,  therefore,  where 
there  is  plenty  of  ventilation.  This  is  an  exceedingly  valua- 
ble remedy,  also,  for  the  itch  of  man,  as  well  as  the  "  mange" 
of  animals.  The  sulphuret  of  potassium  comes  in  the  form 
of  grayish  or  greenish  lumps,  put  up  in  tight  bottles.  It  is 
used  in  photography  and  can  usually  be  bought  at  the  princi- 
pal drug  stores. 

An  equally  useful  preparation,  having  the  same  properties, 
may  be  easily  made  by  taking  fresh  quick-lime,  slacking  it 
gradually  with  water,  and  forming  a  milky  solution  by  the 
addition  of  more  water,  as  in  the  preparation  of  white-wash. 
Into  this  put  as  much  flowers  of  sulphur  as  will  dissolve  by 
boiling  for  some  time.  This  will  produce  a  deep  yellow  solu- 
tion like  that  of  the  sulphuret  of  potassium  in  odor  and 
effects.  It  may  be  diluted  if  too  strong.  It  contains  sul- 
phuret of  calcium,  upon  which  its  usefulness  depends.  Sul- 
phur may  also  be  boiled  in  potash  lye,  to  produce  a  similar 
preparation,  and  to  this,  while  boiling,  tobacco  is  sometimes 
added,  but  the  sulphur  is,  no  doubt,  sufficient  for  all  practical 
purposes.  But  in  no  case  can  we  be  certain  of  destroying  all 
the  eggs  of  these  parasites  by  any  wash  whatever,  that  would 
not  be  dangerous  to  the  animal.  Therefore  the  treatment 
should  be  repeated  two  or  three  times,  at  intervals  of  ten  or 
twelve  days,  in  order  to  destroy  any  young  that  may  have 
hatched  in  the  meantime. 

The  Head-louse  of  man  (Pediculus  capitis  DeGder).     Fig.  30. 
This  is,  probably,  the  best  known  species  of    the  genus 
Pediculus.     It  is  still  sufficiently  common  among  persons  who 
Figure  so.        neglect  personal  cleanliness,  though  much  less 
so  than  it  is  said  to  have  been  formerly ,  when  it 
was  thought  no  disgrace  in  some  parts  of  the 
old  world,  but  was  regarded  as  fashionable, 
rather  than  otherwise.     This  insect  is  almost 
exclusively  confined  to  the  human  head.     It 
attaches  its  eggs  firmly  to  the  hair,  near  the 
roots.     These  eggs  are  long-oval,  with  several 
little  conical  prominences  at  the  large  end, 

Figure    30. — Head-louse    (Pediculus    capitis    DeGcer),     greatly    magnified. 
From  Packard's  Guide. 


40  BOARD  OF   AGRICULTURE. 

which  are  open  at  the  top,  while  the  small  end  oears  a  cluster 
of  bristles.  The  habits  and  treatment  are  too  well  known  to 
need  further  description. 

The  Body-louse  of  Man  (Pediculus  corporis    DeGeer). 

Figure  31. 

This  species  very  closely  resembles  the  last,  but  is  usually 
larger.  It  attaches  itself  especially  to  the  clothing,  and  at- 
tacks various  parts  of  the  body.  It  attaches  its  eggs  chiefly 
to  the  clothing  which  it  frequents,  especially  Figure  si. 

along  the  seams,  and  when  the  clothing  is  sel- 
dom changed,  as  often  necessarily  happens  in 
time  of  war,  it  increases  rapidly  and  becomes 
a  great  source  of  annoyance.  Many  unfortu- 
nate soldiers,  who  were  confined  in  the  south- 
ern prisons  and  prison-pens  during  the  late 
war,  can  testify  to  the  abundance  of  this  par- 
asite under  such  circumstances.  Nor  were 
the  ordinary  camps  free  from  them,  especially  during  active 
campaigns. 

The  Crab-louse  (Phthirius  puUs  Leach).     Figure  32. 

In  the  genus  Phthirius  the  thorax  is  broad  and  not  distinct 
from  the  abdomen,  which  is  flat  and  has  eight  segments,  the 
first  one  being  composed  of  two  united.  Figure  32. 

The  first  pair  of  legs  are  terminated  by 
slender  tarsi,  not  changed  to  grasping 
claws,  but  the  claws  of  the  other  two 
pairs  are  large  and  strong. 

This  species  lives  among  the  hairs  of 
the  pubic  regions  of  man,  and  also, 
though  much  less  commonly,  upon  the  breast,  arm-pits,  in  the 
beard,  eye-brows,  and  also  upon  the  head.  It  sometimes  also 
clings  to  linen  and  clothing,  and,  not  unfrequently,  may  be 
found  in  the  beds  of  those  persons  harboring  them.  They 
may  be  destroyed  by  simple  ointments  and  unguents,  or  by 
the  sulphuret  washes  described  above. 

Figure  31. — Body-louse  (Pediculus  corporis  DeGe  ),  greatly  magnified.  From 
Packard's  Guide. 

Figure  32. — Crab-louse  (Phthirius  pubis  Leach),  much  enlarged.  From  Pack 
ard's  Guide. 


PARASITES  OF  ANIMALS. 


41 


Figure  33. 


The  Cattle-louse  (Hcematopinus  vituli  Denny).  Figure  33- 
In  the  genus  Hcematopinus,  which  includes  a  large  number 
of  species,  the  head  is  obtuse  or  truncated  in  front,  the  middle 
segments  of  the  abdomen  well  separated,  and  the  posterior 
legs  much  the  longest.  The  eyes  are  very  minute.  They  are 
all  small  and  some  are  minute  species. 

H.  •  vituli  is  brownish,  with  a  pale 
abdomen,  the  abdominal  segments 
bearing  lateral  chitinous  pieces,  in 
which  the  spiracles  are  situated.  The 
head  is  elongated  with  a  constriction 
behind  the  antennse.  It  is  about  j1^ 
of  an  inch  in  length,  or  a  little  more. 
It  is  parasitic  both  on  cattle  and  horses, 
and  sometimes  becomes  very  abun- 
dant. 

Another  species  (H.  eurysternus 
Denny),  also  infests  both  cattle  and 
horses.  In  this  the  head,  thorax,  and  feet  are  horn-colored. 
The  thorax  is  very  broad.  The  length  is  about  TV  of  an 
inch. 

The  Hog-louse  (Hcematopinus  suis  Leach).     Figure  34. 
Figure  34.  This  species  is  brown,  with  a  white 

abdomen.  The  spiracles  are  placed  in 
blackish,  horny  plates  along  each 
side  of  the  abdomen.  Length  -J  of  an 
inch. 

H.  stenopsis  infests  the  goat.  It  is 
a  horn-colored  species,  with  along  oval 
hairy  abdomen. 

If.  asini  Denny  is  parasitic  on  the 
ass. 

H.  piliferus  Denny  lives  upon  the  dog.  It  is  uniformly 
horn-colored.  The  body  is  slender  and  covered  with  pale 
hairs.  Length  •£$  of  an  inch. 

Figure  33. — Cattle-louse  (Hcematopinus  vituli  Denny),  much  enlarged.    From 
American  Naturalist. 

Figure  34. — Hog-louse  (H.  suis  Leach),  much  enlarged.  From  Cuvier. 
6 


42 


BOARD  OP  AGRICULTURE. 


MALLOPHAGA  (Bird-lice). 

These  insects  live  both  among  the  feathers  of  birds  and  hair 
of  mammals.  They  are  peculiar  in  having  distinct  jaws  (Figure 
36),  instead  of  a  sucking  tube.  The  body  is  flat,  corneous, 
and  firm  above.  The  head  is  horizontal  and  generally  broad. 
The  antennae  have  three  to  five  joints.  The  mandibles  are 
small  and  hook-like.  The  maxillary  palpi,  when  present,  are 
four-jointed ;  and  the  labial  palpi  two-jointed.  The  legs  are 
short  and  stout,,  with  one  or  two  strong  claws.  There  are  sev- 
eral hundreds  of  species  already  described,  nearly  every  bird 
having  one  or  several  peculiar  species.  They  produce  nearly 
the  same  effects  as  the  true  lice,  and  may  be  destroyed  by  the 
same  remedies. 


Figure  35. 


a        Figure  36. 


The    Turkey-louse   (Goniodes    stylifer   Denny). 

This  is  a  large  species,  conspicuously  marked  with  transverse 
black  bands.  It  is  very  common  both  on  the  domestic  and 
wild  turkey,  together  with  three  or  more  other  species,  one  of 
which  is  much  longer  and  nearly  black.  Some  of  the  other 
species  parasitic  on  the  turkey  are  Liotheum  stramineum 
Nitzsch,  Philoplerus  polytrapeziusNitzsch. 

The  Hen-lice  (Liotheum  pallidum  Nitzsch,  Philoplerus 
variabilis  N.,  P.  heterographus  N.,  P.  dissimilis  N.,  and  P. 

Figure  35. — Turkey-louse  ( Goniodes  stylifer  Denny),  much  enlarged. 
Figure  36. — Head  of  same,  seen  from  below,  more  magnified ;  a,  mouth  organs ; 
b,  antenna.    Both  from  Cuvier. 


PARASITES  OF  ANIMALS. 


43 


ho/og-aster  N.,  Gf-oniocotes  Burnettii  Packard,  Figure  37)  are 
common  enemies  of  domestic  fowls. 


Figure  37. 


Figure  38. 


The  Pigeon-lice  (Liolheum  giganteum  Denny,  Philopterus 
bar/ulus  Nitzsch,  Nirmus  clavicornis,  Goniodes  compar  N.) 
infest  domestic  pigeons. 


Figure  39. 


Figure  40. 


The  Goose-louse  (  Trinotum  squalidum  Denny)  is  found  with 
other  species  on  the  goose. 

The  Duck-lice  (Philopterus  squalidus  Nitzsch),  Figure  38, 
with  other  species,  inhabit  the  common  duck. 

Figure  37. — Hen-louse  (Goniocotes  Burnettii  Pack.).      American    Naturalist. 
Figure  38. — Duck-louse  (Philopterus  squalidus  N.)     From  Gervais. 
Figure  39. — Cat-louse  (Trichodectes  subrostratwN.)  From  American  Naturalist. 
Figure  40. — Goat-louse   (T.  caprce  Packard).      From    American  Naturalist 


44  BOARD  OF  AGRICULTURE. 

The  Peacock-lice  (Philopterus  faldcornis  N.,  P.  reclangula- 
tus  N.)  are  very  common  on  the  peacock. 

The  Cat-louse  (Tricliodectes  subrostratus  Nitzsch),  Figure 
39,  is  one  of  the  parasites  of  the  house  cat.  This  species  is 
whitish,  with  the  head  and  thorax  pale  honey-yellow. 

The  Goat-louse  (  Trichodectes  caprce  Packard,  probably  the 
same  as  T.  limbatus  Gervais),  Figure  40,  lives  with  other 
species  upon  the  domestic  goat.  It  is  reddish  yellow,  trans- 
versely Barred  with  reddish  brown,  the  abdomen  edged  with 
red. 

SUB-CLASS,  ARACHNIDA. 

ACARINA  (Mites). 

These  are  characterized  by  their  simple,'  usually  rounded  or 
oval  bodies,  in  which  there  is  no  distinct  separation  into 
thorax  and  abdomen.  They  have  eight  legs,  which  are  gen- 
erally short,  but  when  young  many  of  them  are  six-legged. 
The  species  are  numerous.  Their  habits  are  very 
diverse  ;  many  are  parasitic  upon  man,  various  quadrupeds, 
birds,  reptiles,  insects,  etc.,  some  externally  and  others  in- 
ternally. Species  have  even  been  found  within  the  abdo- 
minal cavity  and  skull.  Other  species  live  under  the  water, 
and  are  parasitic  on  mollusca.  Many  attack  plants  and  prove 
very  injurious.  Others  are  carnivorous  and  prey  on  small 
insects.  Some,  like  the  meal-mite,  sugar-mite,  cheese-mite, 
fig-mite,  and  many  others  attack  and  greatly  injure  articles  of 
food.  Many  lead  a  solitary,  wandering  life,  others  occur 
together  in  vast  numbers  at  certain  times. 

DERMANYSSUS   DugGS. 

The  insects  of  this  genus  are  small,  soft-bodied  parasites, 
which  infest  various  birds,  bats,  insects,  and  some  of  them 
are  at  times  parasitic  upon  man. 

The  fifth  joint  of  the  palpi  is  smallest.  The  lip  is  sharp. 
The  mandibles  of  the  male  are  forceps-like,  with  long  hooks ; 
those  of  the  female  ensiform.  The  anterior  feet  are  the 
longest.  Young  with  six  legs. 

Dermanyssus  gallinoe  is  found  among  the  feathers  of  the 
domestic  fowl,  and  lives  by  sucking  the  blood. 


PARASITES   OP   ANIMALS.  45 

D.  Grallopavonis  infests  the  turkey.  The  body  is  marked 
by  peculiar,  delicate,  transverse  strias,  and  with  numerous 
small  circular  impressions  on  the  back. 

D.  avium  torments  small  cage  birds,  like  the  canary.  It 
often  takes  refuge  in  cracks  about  the  perches,  which  should 
therefore  be  kept  clean. 

ARGAS  Latreille. 

This  genus  includes  the  famous  Argas  Persicus,  which 
infests  old  dwellings  in  Persia,  especially  at  Mi  ana,  and  is 
said  to  be  so  poisonous  that  its  bite  produces  convulsions  and 
speedy  death  ;  or  even  its  juices,  if  crushed  upon  the  skin, 
may  produce  the  same  results. 

These  are  larger-  than  most  of  the  mites,  and  somewhat 
resemble  the  ticks.  The  body  is  broad-oval  or  roundish. 
The  upper  side  of  the  head  so  projects  as  to  conceal  the  mouth 
parts.  The  jaws  are  suctorial.  The  lower  side  of  the  body 
is  granulous,  not  scaly,  and  covered  by  a  single  piece. 

Argas  reflexus  Latreille  lives  upon  pigeons  and  sucks  their 
blood.  It  especially  infests  the  young,  upon  which  there  are 
sometimes  great  numbers.  The  body  is  marked  with  curious 
tortuous  grooves  and  pits.  The  color  is  yellowish,  but  when 
filled  with  blood  violaceous.. 

IXODES  Latreille.    (Ticks). 

These  are  the  largest  of  the  Acariaris,  and  all  are  parasitic, 
chiefly  upon  quadrupeds  and  reptiles,  but  sometimes  on  birds. 
The  body  is  broad-oval  or  round,  and  when  not  swollen  with 
blood  is  flatish,  and  the  integument  is  firm  and  tough.  Their 
mandibles  (Figure  43,  b,)  are  covered  with  teeth  and  have  ter- 
minal hooks  ;  their  maxilla  are  small,  not  reaching  beyond  the 
beak,  but  bear  a  peculiar  organ  called  the  glossoid  (Figure 
43,  a,)  also  covered  with  hook-like  teeth.  The  legs  are  slender 
and  have  two  claws,  and  in  the  young  have  pads  or  suckers 
(d).  The  young  are  six-legged  (Figure  42).  The  ovarial 
opening  is  near  the  mouth,  between  the  first  pair  of  legs. 
These  parasites,  when  young,  cling  in  large  clusters  to  the 
tips  of  leaves  and  twigs  of  herbs  and  shrubs,  with  part  of 
their  six  slender  legs  extended.  When  brushed  by  a  passing 


46 


BOARD   OF   AGRICULTURE. 


animal,  they  instantly  leave  the  plant  and  quickly  disperse 
over  their  host.  They  insert  their  glossoids  and  mandibles  into 
the  skin,  where  they  cling  firmly  by  means  of  the  numerous 
hooks,  and  live  by  sucking  the  blood.  The  abdomen  soon  be- 
comes very  much  swollen,  and  sometimes  grows  so  large  as  to 
resemble  a  tumor.  They  attack  various  animals  and  even  man, 
indiscriminately.  In  many  parts  of  the  Southern  States  the 
"  wood  ticks  "  are  extremely  troublesome  to  persons  who  have 
occasion  to  go  into  the  forests,  as  well  as  to  animals.  The 
eggs  of  Ixodes  albipictus  are  laid  in  large  masses,  from  the 
first  of  May  until  the  last  of  June.  Early  in  July  the  eggs 
hatch  out  simultaneously,  "  the  shell  opening  like  a  clam." 
The  young  when  first  hatched  have  six  slender  legs. 

Figure  41.  Figure  42. 

tj 


Figure  44.  Figure  43. 

The  Cattle-tick  (Ixodes  bovis).  Figure  41. 
This  is  a  flattened,  leathery,  reddish,  seed-like  species,  with 
an  oblong-oval  body.  It  sometimes  grows  to  be  nearly  half 
an  inch  long.  It  infests  cattle,  and  is  very  troublesome  in  the 
Western  and  Southern  States,  but  is  far  less  common  in  the 
North.  It  also  attacks  the  horse  and  many  other  quadrupeds, 
as  well  as  reptiles,  including  the  rattle-snake. 

Figure  41. — Cattle-tick  (Ixodes  bovis  Riley),  enlarged. 

Figure  42  — Ixodes  albiptctm  Packard ;  six-legged  young,  much  enlarged  ;  d, 
foot  with  sucker. 

Figure  43. — Head  of  the  same,  more  enlarged ;  a,  glossoid ;  b,  mandibles  ;  c 
maxillary  palpi. 

Figure  44. — Adult  of  the  same,  gorged  with  blood,  natural  size.  All  from 
Packard's  Gu,ide. 


PARASITES  OP  ANIMALS.  47 

Ixodes  albipidus  Packard.      Figures  42,  43,44. 

This  was  originally  found  upon  a  tame  moose  by  Mr.  W. 
G.  Hays,  but  doubtless  infests  other  animals. 
Ixodes  unipictus    Packard. 

This  is  about  a  quarter  of  an  inch  long  and  has  an  oval 
form.  Is  is  reddish  brown,  or  mahogany-color,  with  a  central 
silvery  spot  upon  the  back.  It  often  attacks  men  and  vari- 
ous animals.  It  has  been  found  in  New  England,  but  is  more 
common  southward. 

In  Europe,  numerous  species  have   been   found. 

Ixodes  vicinus  is  very  troublesome  to  dogs.  It  is  of  a  brown- 
ish violet  color,  crenulated  posteriorly.  It  has  five  radiating 
brown  spots  and  some  brown  dots. 

Ixodes  reduvius  infest  sheep  and  dogs.  It  has  a  pale  red  or 
yellowish  color,  and  becomes  more  than  a  quarter  of  an  inch 
long.  It  must  not  be  confounded  with  the  ordinary  "  sheep- 
tick"  (see  page  89). 

Mites,  ACARUS  Linn. 

This  genus,  which  originally  included  all  the  mites,  is  now 
restricted  to  those  that  are  allied  to  the  cheese-mite.  The 
mouth  parts  are  prolonged  into  a  rostrum  or  beak.  There  is 
a  constriction  of  the  body  between  the  second  and  third  pair 
of  legs,  dividing  it  somewhat  into  two  parts. 

The  Cheese-mite  (Acarus  siro  Linn.). 
This  species  ordinarily  lives  in  cheese  and  other  articles  of 
food;  but  has  sometimes  been  observed  parasitic  upon  man,  in 
certain  diseased  conditions. 

The  Meal-mite    (Acarus  farince  De  Ge*er). 

This  species,  found  in  meal  and  flour  that  has  been  in- 
jured is  sometimes  accidentally  swallowed  while  living. 

Acarus  dysmterice  Linn,  was  found  living  in  the  excreta  of 
a  person  attacked  by  violent  dysentery.  It  also  sometimes  oc- 
curs in  large  numbers  about  wine  and  beer  casks,  and  may 
therefore  be  swallowed  accidentally. 

Glycipliagus  hippopodos  has  been  found  in  the  ulcerated  feet 
of  horses.  A  species  of  mite  also  occurs  in  the  diseased 
feet  of  sheep. 


48  BOARD  OP  AGRICULTURE. 

Mange-insect  of  the  Horse  {Psoroptes  equi  Gervais). 

This  insect  is  readily  visible  to  the  naked  eye  and  swarms 
on  horses  afflicted  with  the  mange,  which  is  a  disease  anala- 
gous  to  the  itch  in  man.  It  has  a  soft,  depressed  body,  spiny 
beneath  at  the  base  of  the  legs  and  on  the  thorax.  One  or 
both  £>f  the  two  posterior  pairs  of  feet  bear  suckers,  and  all 
are  more  or  less  covered  with  long  slender  hairs. 

Figure  45. 

Fig.  46. 


This  insect  may  be  destroyed  by  the  same  remedies  used  for 
lice  and  for  the  human  itch.  The  best  remedy  is  probably  the 
solution  of  sulphuret  of  potassium,  described  on  page  109. 

The  Itch-insect  {Sar  copies  scabieiL&tY.').  Figure  47. 
This  is  a  very  minute,  whitish  species,  barely  visible  to  the 
naked  eye,  unless  on  a  dark  surface.  It  has  been,  in  former 
times,  the  subject  of  many  lengthy  discussions,  in  reference 
to  its  causing  the  itch.  It  is,  however,  at  the  present  time 
fully  ascertained  to  be  the  sole  cause  of  the  ordinary  itch, 
though  other  species  of  similar  parasites  may  cause  different 
varieties  of  itch.  The  body  is  rounded  and  soft,  with  small 
round  pustules  on  the  middle  of  the  back,  and  with  radiating 
lines  or  ridges,  the  sides  of  the  body  and  legs  bearing  long 
bristle-like  hairs.  The  mandibles  are  needle-like.  The 
female  is  largest  and  has  the  two  pairs  of  hind  legs  but  little 
developed,  ending  a  bristle  ;  in  the  male  they  are  well  devel- 
oped and  terminate  in  a  slender  sucker.  These  creatures,  as 
seen  under  the  microscope,  have  something  of  the  unwieldy 

Figure  45. — Psoroptes  equi  Gervais,  female ;  ventral  side,  much  enlarged. 
Figure  46. — Head  of  the  same,  more  magnified.   Both  from  Cuvier. 


PARASITES   OF   ANIMALS. 


49 


Figure  47. 


appearance  of  a  tortoise,  and  are  ordinarily  sluggish,  yet  they 
are  capable  of  leaping  to  a  considerable  distance.  They  bury 
themselves  in  the  human  skin,  especially  in  the  more  delicate 
and  less  exposed  parts,  and  excavate  minute  galleries  for  them- 
selves, in  a  manner  something  like  that 
in  which  moles  excavate  galleries  in 
the  soil.  These  galleries  are  at  first 
perpendicular,  and  then  go  off  horizon- 
tally to  some  distance.  The  females 
lay  their  eggs  in  these  galleries  as 
they  progress. 

These  mining  and  boring  operations 
cause  much  irritation  of  the  nerves  of 
the  skin  and  induce  an  intolerable  itch- 
ing, and  the  inflammation  that  they 
cause  produces  pustules,  filled  with  a 
watery  exudation.  The  insects  them- 
selves are  not  found  in  the  pustules  but 
in  their  minute  galleries,  off  to  one 

side,  the  pustule  generally  marking  the  place  where  they  en- 
tered. The  itch  is  contagious,  simply  because  the  insects, 
especially  in  their  young  and  more  active  state,  pass  from  one 
person  to  another,  or  are  transmitted  by  clothing.  They  are 
most  active  at  night  and,  therefore,  sleeping  with  an  infested 
person  is  pretty  sure  to  be  attended  by  the  transfer  of  the 
insects.  The  longer  the  parasites  are  neglected,  the  more 
numerous  they  become.  .The  increase  is,  however,  quite  slow 
at  first,  owing  to  the  small  number  of  eggs.  There  are 
various  remedies  for  this  disease,  but  the  different  preparation 
of  sulphur  are  no  doubt  the  best  and  safest.  The  solutions 
of  sulpha  ret  of  potassium,  described  on  page  109,  is  probably 
the  simplest  and  most  efficacious  preparation  for  this  purpose. 
Its  use  should  be  accompanied  by  a  thorough  change  of  gar- 
ments and  bedding,  and  it  should  be  used  by  all  the  members 
of  an  infected  family  simultaneously.  It  should  be  appliedat 


Figure  47. — Itch-insect  (Sarcoptes  scabiei  Latreille),  female,  upper  side,  much 
enlarged.     From  Guerin. 

7 


09  BOARD   OF  AGRICULTURE. 

least  three  times,  at  intervals  of  three  or  four  days,  to  destroy 
the  young  as  fast  as  they  hatch. 

Species  of  Sarcoptes,  closely  allied  to  the  itch-insect,  have 
been  found  on  the  domestic  animals,  causing  diseases  analo- 
gous to  the  itch  in  man.  Such  diseases,  caused  by  quite  a 
number  of  distinct  parasites,  are  called  "  mange."  They 
have  been  observed  on  the  cat,  dog,  camel,*  and  hog. 

The  genus  Dermatodectes  is  closely  allied  to  Sarcoples,  and 
the  species  likewise  live  on  animals,  burrowing  in  the  skin. 
D.  bovis  infests  cattle,  and  D.  ovis  lives  in  the  skin  of  sheep. 
The  genus  Dermaleichus  infests  birds  in  a  similar  manner. 

All  these  parasites  should  be  treated  like  the  itch-insect  of 
man.  The  sulphuret  of  potassium  solution,  applied  with  a 
brush  that  has  long  bristles,  like  a  white-wash  brush,  is 
probably  the  best  and  simplest  remedy. 

The  Face^mile  (Demodex  folliculorum  Owen).     Figure  48. 

This  singular  but  minute  parasite  lives  in  the  diseased  and 
enlarged  follicles  in  the  skin  of  the  human  face,  especially  in 
those  about  the  nose  and  chin.     The  follicles,  when  thus  dis- 
eased,  are   enlarged   and  filled   with   a  thickened 
sebaceous  matter,   the   orifice    being    usually    ob-  risure  48- 
structed  by   a  hardened,   blackish    substance.     If 
these  be  pressed,  and  the  matter  which  is  forced  out 
be  carefully  examined  with  a  microscope,  it  will  often 
be  found  to  contain  numerous  specimens  of  this  minute 
creature,  in  all  stages  of  development.     A  drop  of 
oil  or   ether   applied  to  the  sebaceous  matter,  to 
dissolve    the  fatty  parts,  will    render   them   more 
readily  visible.     The  young  ones  have  but  six  short 
legs  ;  the  adults  have  eight  legs   and  a  worm-like 
body,  as  represented  in  Figure  48.     It  has  been  thought  that 
the  "  barber's  itch"  is  caused  by  this  parasite,  but  I  do  not 
know  that  this  has  been  fully  established. 

*S.  dromedarii,  of  the  camel,  is  sometimes  communicated  to  man,  causing  a 
form  of  itch  worse  than  the  ordinary,  owing  to  its  great  size  and  numerous  spines. 

Figure  48. — Face-mite  (Demodex  folliculorum  Owen,  or  Simonea  folliculorum  of 
some  authors),  much  enlarged.  From  Packard's  Guide. 


PARASITES  OF    ANIMALS.  51 

The  same  species,  or  one  very  closely  allied  to  it,  occurs  in 
the  skin  of  the  dog  and  other  domestic  animals,  producing 
some  forms  of  the  "  mange."  These  parasites  will  probably 
be  destroyed  by  the  same  remedies  that  are  effective  against 
the  itch-insect. 


Library. 

SECOND  LECTURE 


The  Internal  Parasites  of  Domestic  Animals; 


THEIR  EFFECTS  AND  REMEDIES: 


The  parasites  of  man  are  so  intimately  connected  with  those 
of  his  domesticated  animals,  that  it  is  impossible  to  discuss 
them  separately.  Indeed,  many  of  the  human  parasites  in- 
habit also  the  hog,  cattle,  sheep,  and  the  dog,  in  certain  stages 
of  their  development,  and  nearly  all  the  most  dangerous  kinds 
are  derived,  either  directly  or  indirectly,  from  those  animals. 
While  in  return  mankind  furnish  to  them  the  eggs  of  several 


52  BOARD   OF  AGRICULTURE. 

of  their  worst  parasites.  Thus  some  of  these  creatures  are 
kept  in  existence  solely  by  reason  of  the  peculiar  relations  ex- 
isting between  man  and  his  brute  dependents.  This  is  partic- 
ularly the  case  in  respect  to  the  two  most  common  tape-worms 
of  man,  derived  respectively  from  the  flesh  of  cattle  and  hogs, 
in  which  the  young  worms  live.  These  two  worms  appear  to 
be  capable  of  coming  to  maturity  only  in  the  human  in- 
testine. 

Most  of  these  internal  parasites  belong  to  the  great  class  of 
articulated  animals  known  as  Worms,  constituting,  however, 
several  distinct  orders,  which  are  often   collectively   called 
Helminths.     The  orders  of  parasitic  worms  are  much  lower 
in  rank  than  those  that  include  the  independent  kinds,  like 
the  numerous  species  of   free  marine  worms,  or  Annelids, 
many  of  which  have  beautiful  gills  and  locomotive  organs,  a 
very  complex  circulation,  red  blood,  and  a  well-organized  head, 
eyes,  mouth,  and  intestine  ;  to  such  worms  the  common  earth- 
worms, or  angler-worms,  are  also  allied,  although  destitute  of 
gills.     But  the   parasitic   worms  never  have  red  blood  nor 
special  organs  for  breathing,  and  rarely  for  locomotion  ;  most 
have  no  distinct  organs  of  sense,  and  many  have  no  head  and 
no  intestine.     The  reproductive  system  is,  however,  always 
very  highly  developed,  and  most  of  them  are  exceedingly 
prolific.     This  is  essential  to  their  existence,  for  it  is  often  only 
by  mere  chance  that  any  of  the  eggs  or  young  reach  the 
peculiar  habitats  in  which  alone  they  can  grow  to  maturity. 

The  int<irnal  parasites  of  animals  have  long  been  the  sub- 
ject of  laborious  and  careful  research  by  many  of  the  ablest 
naturalists  and  physiologists,*  owing  to  the  remarkable 

*The  following  are  some  of  the  more  important  and  useful  of  the  recent  gen- 
eral works  on  parasitic  worms : 

Felix  Dajardin,  Histoire  naturelle  des  Helminthes  au  vers  intestinaux,  8vo, 
with  plates,  Paris,  1845.  (Suites  a  Buffon.) 

C.  M.  Diesing,  Systema  Helminthum.     Two  volumes,  8vo.    Vindobonae,  1850. 

J.  Leidy.  A  Flora  and  Fauna  within  living  animals.  Smithsonian  contribu 
tions,  1852. 

C.  Davaine,  Traite"  des  Entozoaires  et  des  mala-lies  vermineuses  de  rhomme  et 
des  animaux  domestiques,  8vo,  930  pages,  with  88  figures.     Paris,  1860. 

D.  F.  Weinland.    An  Essay  on  the  tape-worms  of  man ;   8vo  pamphlet,  with 
figures.     Cambridge,  Mass.,  1858. 

T.  S.  Cobbold.  Entozoa  ;  an  Introduction  to  the  study  of  Helminthology,  with 


PARASITES  OP   ANIMALS.  53 

peculiarities  of  their  structure,  habits,  andmodes  of  reproduc- 
tion, as  well  as  to  their  great  practical  importance  with  refer- 
ence to  human  health  and  property. 

The  total  number  of  species  hitherto  described,  from  all 
animals,  is  more  than  2,000.  Of  these  upwards  of  100  species 
are  found  in  domestic  animals  and  man. 

The  parasitic  worms  of  man  and  domestic  animals  are  nat- 
urally divided  into  four  principal  orders,  which  are  character- 
ized by  important  anatomical  and  physiological  peculiarities. 
I.   CESTODES.  (Tape-worms). 

This  order  includes  the  numerous  kinds  of  tape-worms  and 
their  young,  the  "  measles,"  hydatids,  and  bladder-worms, 
found  in  more  or  less  abundance  in  all  classes  of  vertebrate 
animals,  as  well  as  in  insects,  mollusca,  etc.  These  tape- 
worms belong  to  three  very  distinct  families  and  to  numerous 
genera.  About  250  species  have  been  hitherto  described. 

These  worms  in  the  sexually  mature  condition  have  a  more 
or  less  enlarged  roundish,  oval,  angular,  or  lobedhead,  desti- 
tute of  a  mouth,  but  provided  with  two  or  four  suckers,  or 
pits,  and  often  with  one  or  four  proboscis-like  organs,  sur- 
rounded by  hooks,  by  means  of  which  they  fasten  themselves 
securely  to  the  mucous  membrane  of  the  intestine  of  the 
animal  in  which  they  live.  There  is  no  intestine  or  other  di- 
gestive system.  The  head  is  followed  by  a  series  of  many 
flattish  joints  or  segments,  those  near  the  head  being  small 
and  short,  while  those  that  are  more  distant  are  larger  and 
usually  oblong  or  squarish.  These  joints,  as  they  mature,  are 
spontaneously  detached  and  may  enjoy  a  short  independent 
existence,  and  are  then  called  proglottides.  Each  joint  con- 
tains distinct  male  and  female  reproductive  organs,  and 
matures  a  vast  number  of  eggs,  which  are  generally  liberated 

reference  more  particularly  to  the  internal  parasites  of  man.  Large  8vo,  480 
pages,  *with  numerous  figures  and  21  plates.  London,  1864. 

J.  L.  W.  Thudichum.  On  the  Parasitic  Diseases  of  Quadrupeds  used  for  food. 
In  the  Seventh  Report  of  the  medical  officer  of  the  Privy  Council,  p.  303.  Lon- 
don, 1865. 

T.  S.  Cobbold.  Tape-worms  (Human  Entozoa),  their  sources,  nature,  and  treat- 
ment; 12mo,  83  pages,  with  figures.  London,  1866. 

R.  Leuckart,  Die  Menschlichen  Parasiten,  und  die  von  ihnen  herrahrenden 
Krankhciten.  Two  volumes,  8vo,  with  numerous  figures.  Leipzig  and  Heidel- 
berg, 1862  to  1868. 


54  BOARD   OP  AGRICULTURE. 

from  the  enclosing  proglottid  after  the  latter  has  been  dis- 
charged from  the  animal  that  nourishes  the  parent  tape-worm. 
The  eggs  usually  escape  by  the  bursting  of  the  integument  of 
the  proglottid,  owing  to  their  increase  in  size,  as  the  embryos 
develop  within  them.  While  attached  to  the  tape-worm  the 
successive  joints  are  connected -together  by  longitudinal  tubes 
or  ducts  that  pass  through  the  entire  length  of  the  worm-,  gen- 
erally one  near  each  edge  of  the  joints.  These  are  connected 
together  by  transverse  tubes  in  each  end  of  the  successive 
joints  (Figure  54). 

The  reproductive  organs  occupy  variously  branched  and 
ramified  cavities  in  the  interior  of  the  joints,  communicating 
by  ducts  with  the  external  male  and  female  organs,  which  are 
placed  side  by  side,  either  on  the  edge  of  each  joint,  as  in 
Tcenia,  or  in  the  middle  of  one  side,  as  in  BotTiriocephalus. 
The  remainder  of  the  joint  is  composed  of  a  firm,  more  or 
less  solid  tissue. 

All  the  species  of  this  order  undergo  remarkable  metamor- 
phoses ;  the  larva  living  in  one  animal  must  be  swallowed  by 
another  before  it  can  become  mature. 

II.    TREMATODES.  (Flukes). 

This  order  includes  a  great  number  of  more  or  less  flattened 
worms,  of  which  the  "  fluke,"  frequently  found  in  the  liver  of 
sheep,  causing  the  "  rot,"  is  an  example  (Figure  73). 

The  body  is  generally  broad  and  more  or  less  oval,  some- 
times elongated,  but  never  divided  into  distinct  joints.  On 
the  lower  side  there  is  usually  one  or  two  prominent  suckers, 
and  sometimes  several.  There  is  a  small  mouth  on  the  lower 
side,  usually  near  one  end,  but  no  head.  The  mouth  com- 
municates with  a  small,  dilated  oasophagus  or  stomach,  and 
this  with  a  more  or  less  branched  and  subdivided,  sometimes 
arborescent,  intestine,  the  branches  ending  in  closed  tubes  or 
blind-sacs.  Another  system  of  branched  and  often  much  sub- 
divided tubes  arises  in  the  more  or  less  solid  tissues  of  the 
body.  These  tubes  are  at  first  small,  like  rootlets,  but  grad- 
ually uniting  into  larger  and  larger  branches,  finally  empty 
their  contents  into  one  or  two  main  trunks,  which  open  ex- 
ternally by  one,  or  sometimes  two  orifices,  near  the  posterior 
end  of  the  body.  This  is  called  the  water-vascular  system, 


PARASITES   OF   ANIMALS.  55 

and  is  supposed  to  perform  the  office  of  excretory  organs, 
analogous  to  the  kidneys  and  liver  of  vertebrate  animals.  In 
the  central  region  of  the  body  there  is  a  well  developed  repro- 
ductive system,  both  male  and  female  organs  being  generally 
contained  in  the  same  individual  worm  ;  but  in  some  species 
the  sexes  are  separate.  All  the -rest  of  the  body,  around  these 
organs,  is  composed  of  a  rather  firm  and  solid  tissue,  the  or- 
gans not  being  contained  in  a  distinct  cavity. 

The  species  constituting  this  order  are  very  numerous,  be- 
longing to  several  distinct  families  and  many  genera.  About 
400  species  have  been  described.  They  are  found  in  all  classes 
of  vertebrate  animals,  and  are  numerous  in  their  larval  states 
in  many  invertebrates,  especially  in  fresh-water  snails.  They 
particularly  abound  in  fishes,  frogs,  and  aquatic  birds.  Nearly 
all  the  species  undergo  very  remarkable  transformations,  with 
alternate  generations,  some  of  them  passing  different  stages  of 
their  lives  free  in  water,  and  then  in  two  or  more  distinct  an- 
imals, as  parasites.  So  that  the  adult  forms,  found  in  the 
higher  animals,  are  generally  derived  from  larvae  swallowed 
in  small  mollusks,  like  the  river  snails,  and  perhaps  in  insects. 

III.     ACANTHOCEPHALA.    (Thorn-headed  worms.) 

This  order  includes  elongated,  more  or  less  cylindrical 
worms,  usually  with  the  body  encircled  by  distinct  transverse 
ridges  and  wrinkles,  and  which  have  at  the  anterior  end  a 
prominent,  elongated  or  conical,  retractile  proboscis,  covered 
with  numerous  recurved  hooks,  by  means  of  which  they  at- 
tach themselves  to  the  mucous  membrane  in  the  intestine  of  the 
animals  that  they  inhabit.  The  body  contains  a  large  cavity, 
in  which  the  reproductive  organs  are  contained.  The  sexes  are 
distinct.  The  ovary,  situated  in  the  anterior  part  of  the  body, 
sets  free  large  roundish  masses  of  cells  from  which  the  ova  are 
afterward  developed,  while  these  masses,  or  "  cocoons,"  are 
free  in  the  abdominal  cavity,  each  mass  containing  a  large 
number  of  eggs,  often  several  hundred.  In  the  male  the  two 
testicles  are  attached  to  the  lower  closed  end  of  the  digestive 
sac,  and  are  connected  by  ducts  with  the  intromittent  organ, 
which  is  a  slender  spiculum,  enclosed  in  a  sheath,  situated  at 
the  posterior  end  of  the  body. 


56  BOARD  OP   AGRICULTURE. 

4| 

Many  observers  state  that  these  worms  have  no  mouth  and 
no  digestive  organs  whatever,  but  obtain  their  nutriment  by 
absorbing  the  nutritive  materials  by  which  they  are  surrounded 
in  the  intestine  of  their  host  directly  into  their  own  tissues, 
after  the  manner  of  the  tape-worms.  M.  Lespes*  states,  how- 
ever, that  Echinorhynchus  clauceveps,  found  in  the  minnow,  etc., 
has  a  complete  alimentary  system.  The  mouth  is  very  small,  in 
form  of  a  pore,  opening  at  the  end  of  the  proboscis  and  raised 
upon  a  small  mobile  papilla.  This  mouth  communicates  with 
a  short  digestive  cavity,  in  the  form  of  a  blind  sac.  He  states 
that  he  has  seen  the  refuse  of  the  food  ejected  from  the  mouth. 

Upwards  of  100  species  of  these  worms  have  been  described, 
nearly  all  of  which  are  referred  to  the  genus  Uchinorhynchus. 

They  are  especially  abundant  in  birds  and  fishes. 

Those  species  in  which  the  development  has  been  studied, 
have  a  kind  of  alternate  generation,  the  young  embryo  be- 
ing very  different  from  the  parent,  and  afterward  developing 
in  its  interior  another  form,  which  in  turn  becomes  like  the 
grandparent.  M.  Lespes  states  that  E.  clavceceps  produces 
•"  cocoons  "  containing  150  to  200  eggs.  The  embryos  devel- 
oped in  the  eggs  are  capable  of  moving  while  still  in  the  shell, 
and  remain  alive  for  a  year.  On  feeding  a  snail  with  food 
containing  these  eggs,  they  hatched  in  his  intestine,  and  the 
free  embryos  were  quite  lively  and  active,  and  furnished  with 
two  pairs  of  hooks  for  boring  purposes.  They  had  consider- 
able resemblance  to  the  free  embryos  of  tape-worms  and  no 
doubt  have  similar  habits,  but  they  failed  to  undergo  their 
transformations  in  the  snail. 

Leuckart  fed  the  eggs  of  E.  proteus,  found  in  the  trout  and 
other  fishes,  to  a  small  crustacean,  Gammarus  pulex.  The  eggs 
hatched  in  a  few  days  and  the  young  embryos  bored  their  way 
through  the  intestine  into  the  general  cavity  of  the  body,  some 
of  them  penetrating  into  the  limbs.  In  the  course  of  three 
weeks  they  grew  larger  and  the  granular  mass  still  in  the  inte- 
rior of  the  body  of  these  embryos  developed  into  a  distinct  or- 
ganism, which  afterwards  developed  a  proboscis,  muscles,  and 
the  other  peculiar  organs  of  an  Echinorhynchus, becoming  gradu- 

*Journal  de  1'  Anatomic,  1864,  p.  683  ;  Gunther's  Zoological  Record,  1865,  p.  747. 


k    PARASITES  OF  ANIMALS.  57 

ally  more  and  more  like  its  grandparent.  It  finally  fills  up 
the  whole  interior  of  the  body  of  the  enclosing  embryo,  sexual 
organs  appear,  and  then  the  outer  skin  of  the  latter  is  cast  off*. 
Thus  the  young  Echinorhynchus.  is  formed,  but  in  order  to  be- 
come mature  it  must  be  swallowed,  with  its  crustacean  host, 
by  some  fish.  In  the  intestine  of  the  fish  it  becomes  sexually 
mature  in  about  a  week. 

The  giant  Ecliinorhynchus  of  the  hog  (^JE.  gigas).  Figure  74, 
is  the  only  species  known  to  infest  domestic  quadrupeds. 
IV.     NEMATODES.      (Round-worms). 

This  order  includes  a  great  number  of  worms,  which  occur 
in  all  classes  of  animals,  both  vertebrates  and  invertebrates, 
together  with  some  that  are  not  parasitic,  but  live  in  water, 
moist  earth,  or  decaying  animal  or  vegetable  matters.  They 
are  much  more  highly  erganized  than  those  of  the  preceding 
orders.  The  pin -worms  of  children,  the  common  round-worms 
of  man  and  domestic  animals,  and  the  notorious  Trichina  spi 
ralis  are  examples  of  this  order.  (See  figures  76  to  83.) 

These  worms  are  almost  without  exception  long,  round,  and 
rather  slender,  varying  in  length  from  a  tenth  of  an  inch  or 
less  to  three  feet,  or  even  more,  and  usually  tapering  to  one  or 
both  ends.  The  external  surface  of  the  body  Js  generally 
smooth  and  uniform,  without  suckers  or  other  appendages.  In 
the  interior  of  the  body  there  is  a  continuous  visceral  cavity, 
containing  a  distinct  digestive  system,  the  intestine  generally 
extending  from  one  end  of  the  body  to  the  other,  and  well  de- 
veloped reproductive  organs,  the  sexes  being  separated.  The 
mouth  is  usually  at  the  smaller  end  of  the  body  and  is  often 
surrounded  by  papillae  or  other  organs.  Some  of  the  species 
are  viviparous,  like  Trichina ;  others  produce  eggs,  like  the  com- 
mon round-worms  and  pin-worms.  There  is  great  diversity 
in  their  habits  and  modes  of  development.  Some  of  them 
pass  through  alternate  generations  and  remarkable  trans- 
formations, living  in  some  cases,  like  Trichina,  in  two  different 
animals  in  the  larval  and  adult  states,  in  other  cases  pass- 
ing the  young  states  in  the  water,  as  free  worms,  and  after- 
wards becoming  parasitic,  when  swallowed  by  the  proper  ani- 
mal, in  which  alone  they  develop  their  reproductive  organs 


'58  BOARD    OF   AGRICULTURE. 

and  become  mature.  Some  species  seem  to  have  a  much 
more  simple  history  during  development.  There  are  but  few 
species,  however,  of  which  the  complete  history  is  known. 
The  Trichina  spiralis  is,  perhaps,  better  understood  in  all 
stages  of  its  life  than  any  other  species.  Important  discov- 
eries remain  to  be  made,  without  doubt,  concerning  other 
species  that  infest  our  own  bodies,  as  well  as  those  of  our 
domestic  animals ;  At  present  the  complete  histories  of  the 
two  commonest  human  parasites,  the  round-worm  and  pin- 
worm,  are  still  unknown,  although  they  have  been  most  care- 
fully investigated  and  experimented  upon  by  many  able  nat- 
uralists. 

Of  this  order  about  1,000  species  have  been  already  described, 
but  it  is  probable  that  a  considerable  number  of  these  will  event- 
ually prove  to  be  only  the  young  of  others.  They  particu- 
larly abound  in  mammals,  birds,  and  fishes,  inhabiting  the  in- 
testine, stomach,  windpipe,  lungs,  kidneys,  muscles,  brain,  and 
various  other  parts  of  the  body.  Twelve  species  or  more  are 
liable  to  infest  human  beings. 

ACARINA. 

In  addition  to  the  internal  parasitic  worms,  there  are  certain 
parasites  which  belong  to  other  groups.  Among  these  are 
certain  forms  of  acarina,  or  mites,  some  of  which  are,  perhaps, 
only  accidentally  parasitic,  like  the  Acarus  dysenteries  mentioned 
in  our  previous  lecture.  But  the  genus  Pentastoma  includes 
species  which  are  true  parasites  and  have  nearly  the  same 
habits  as  some  of  the  parasitic  worms,  which,  indeed,  they 
closely  resemble  in  general  appearance.  Formerly  these  par- 
asites were  regarded  as  worms  by  all  authors,  but  they  are 
now  generally  referred  to  the  Acarina,  although  they  differ 
greatly  from  the  more  typical  forms.  One  of  these  species 
is  represented  in  Figure  84. 

PROTOZOA. 

Several  genera  and  species  of  infusoria  have  been  found  liv- 
ing in  the  human  body,  or  in  the  excreta,  especially  of  pa- 
tients attacked  with  certain  contagious  diseases.  The  effects 
of  these  parasites  and  their  relations  to  diseases  are  not  well 
understood. 


PARASITES  OF   ANIMALS.  59 

Lists  of  the  Parasites  of  Man  and  Domestic  Animals. 

The  number  of  species  of  these  internal  parasites  now 
known  is  upwards  of  100.  Therefore  it  will  be  impossible,  at 
this  time,  to  do  more  than  enumerate  the  species,  with  their 
principal  modes  of  occurrence,  and  then  describe  more  fully 
some  of  the  most  important  kinds,  with  their  effects  and  rem- 
edies, so  far  as  space  will  admit.  It  is  hoped  that  the  lists 
will  serve  as  a  key  or  index  for  those  who  wish  to  pursue  the 
subject  further,  in  the  more  extensive  works  upon  this  subject. 

INTERNAL  PARASITES  OF  MAN. 

CESTODES. 

Iccnia  solium  Linnaeus.  Intestine,  young  in  hog ;  common. 
T.  mediocancUala  Kuch.  Intestine,  young  in  beef;  common. 
T.  flauopunctata  Weinland.  Intestine  ;  one  case  only,  in  the 

United  States. ' 
T.    lophosoma    Cobbold.      Intestine,    larva  unknown ;    one 

case. 

T.  elliptica  Batsch.  Intestine  ;  rare,  common  in  cats. 
T.  nana  Siebold.  Intestine  ;  only  observed  in  Egypt. 
Bothriocephajus  latus  Bremser.  Intestine,  larva  in  fish  (?)  ; 

Europe,  rare  in  America. 
B.  cordatus  Leuckart.     Intestine  ;  common  in  Greenland. 

In  the  larval  state. 

Tccnia  solium  Linn.     In  muscles,  brain,  eye,  etc. ;  not  rare. 

T.  marginata  Batsch.     Abdominal  viscera ;  very  rare. 

T.  acanthotrias  Weinland.  In  muscles,  mature  worm  un- 
known ;  observed  once  only,  in  Virginia. 

T.  echinococcus  Siebold.  Tumors  in  liver,  brain,  lungs,  ab- 
domen, muscles,  etc.,  adult  in  dog ;  common. 

TREMATODES. 

Billiarzia  Jicematobia  Cobbold.  Inhabits  the  blood-vessels,  es- 
pecially the  portal  veins  and  those  of  the  kidneys  and  blad- 
der ;  very  common  in  Africa,  producing  a  very  serious  disease. 

Fasciola  hepatica  Linnaeus.  Gall-bladder  and  ducts,  and 
sometimes  beneath  the  skin  ;  common  in  sheep,  rare  in 
man. 


60  BOARD   OP   AGRICULTURE. 

Distoma  lanceolatum  Mehlis.     Gall-ducts  ;  rare. 

D.  crassum  Busk.     Duodenum ;  one  case. 

D.  heterophyes  Siebold  and  Bilharz.     Small  intestine,  in  large 

numbers  ;  two  cases,  in  Egypt. 
D.  ophthalmobium  Diesing,  (perhaps  young  of  D.    lanceola- 

tum).     Eye,  several  together  ;  two  cases. 
Tetrastoma  renale  Delle  Chiage.     Kidney ;  one  case. 
Hexanthyridium  pinguicola  Treutler.     In  an  ovarian  tumor  ; 

one  case. 
H.  nenat  wn  Treutler,  (probably  young).     Veins  ;  rare. 

NEMATODES. 

Trichina  spiralis  Owen.  Adult  in  intestine,  young  in  muscles  ; 
common. 

Trichocephalus  dispar  Rudolphi.     Small  intestine. 

Filaria  trachealis  Cobbold.     Trachea  and  larynx  ;  one  case. 
' F.  lentis  Diesing,  (larval  form).     Eye;  very  rare. 

Dracunculus  medinensis.  Gmelin,  (Guinea-worm).  In  the 
connective  tissue  beneath  the  skin  and  among  the  muscles. 
Yery  common  in  Arabia,  Guinea,  Upper  Egypt,  and  other 
parts  of  tropical  Asia  and  Africa  ;  also  in  some  parts  of  the 
West  Indies. 

D.  oculi  Diesing,  (loa).  Orbit  of  the  eye,  in  the  conjunctiva, 
etc.  Not  uncommon  in  tropical  Africa  and  America,  chief- 
ly in  the  African  races. 

Oxyuris  vermicularis  Brernser,  (pin-worm).  In  the  large  in- 
testine, chiefly  in  the  rectum  and  near  the  anus,  sometimes 
in  the  genital  passage  ;  very  common,  especially  in  chil- 
dren. 

Ascaris  lumbricoides  Linn.,  (round- worm).  Intestine,  some- 
times ascending  into  the  stomach,  rarely  passing  into  the 
abdominal  cavity  by  perforating  the  intestine  ;  very  com- 
mon. 

A.  mystax  Rud.  (round-worm  of  cats).  Intestine  ;  rare  in 
man,  common  in  the  cat. 

Eustrongylus  gigas  Diesing,  (kidney-worm).  Kidney  ;  rare 
in  man. 

Strongylus  bronchialis  Cobbold.     Bronchial  tubes  ;  very  rare. 


PARASITES   OP   ANIMALS.  61 

Dochmius    duodenalis    Leuckart.      Small    intestine ;    Italy, 
much  more  common  in  Egypt,  causing  very  serious  disease. 

ACARINA. 

Pentastoma  dentimlatum  Rud.     (Probably  the  young  of  P. 

tcenioides  of  the  dog.)     In  cysts  on  the  liver,  etc.  ;  not  very 

rare. 
P.  comtrictum  Siebold.     Liver  and  lungs  ;  common  in  Egypt. 

PROTOZOA. 

Paramecium  coli  Malmstein.    Colon,  excreta. 
Cercomonas  intesiinalis  Lambl.  ((7.  ^ommisDavaine).     Intes- 
tine ;  from  a  cholera  patient. 
Variety  B.    From  a  typhoid  fever  patient. 
C.  urinarius  Hassal.     In  urine. 
C.  saltans  Ehrenberg. 

Trichomonas  vaginalis  Donne".    Vagina,  in  mucus. 
PsorospermSj  (perhaps  the  eggs  of  Distoma). 

In  addition  to  the  preceding  species  of  true  parasites, 
various  kinds  of  insect  larvae  have  been  known  to  live  for  a 
time  in  the  human  stomach  and  intestine,  from  which  they 
have  been  discharged  either  by  vomiting  or  purging. 

Among  the  most  common  larvae  that  may  thus  live  in  the 
human  body  are  those  of  the  various  species  of  meat-flies,  blue- 
bottle-flies, blow-flies,  or  flesh-flies  (see  page  101),  and  those 
of  the  house-fly.  Several  species  of  the  genus  Homalomyia 
have  also  been  known  to  occur  in  this  way,  the  eggs  or  larvae 
having  been  swallowed  with  fruit,  and  more  especially  in  de- 
cayed fruit,  in  which  they  naturally  live.*  Such  larvae  often 
cause  considerable  irritation  of  the  intestine,  and  diarrhoea, 
but  as  their  life  in  the  larval  state  is  very  short,  they  must 
soon  pass  from  the  intestine  or  perish  in  it. 

INTERNAL  PARASITES  OF  THE  DOG. 

CESTODES. 

Tcenia  echinococcus  Siebold.  Intestine,  many  together ;  larvae 
in  sheep,  cattle,  and  man  ;  common. 

*These  insects  are  well  described  by  Mr.  B.  D.  Walsh  in  the  American  En- 
tomologist, vol.  II,  page  137,  1870. 


62  BOARD  OP  AGRICULTURE. 

T.  coenurus    Kiich.     Intestine,   many   together ;    not   rare. 
Larvae  in  sheep. 

T.  marginata  Batsch.     Intestine,   few  or  singly ;    common. 
Larvae  in  sheep  and  cattle. 

T.  serrata  Goeze.     Intestine  ;  common.     Larvae  in  rabbits. 

T.  canis-lagopodis  Rud.    Intestine  ;  in  Iceland  common.    Lar- 
vae unknown.    Perhaps  same  as  T.  Utter ata  Batsch. 

T.  cucumerina  Bloch.      Intestine  ;  very  common.     Larvae  un- 
known. 

T.  solium  Linn.,  (in  cysticercus  state).     Muscles,  brain,  etc. 

Bothriocephalus  lalus  Bremser.     Intestine  ;    not  common. 

B.  cordatus   Leuckart.     Intestine ;  very  common  in  Green- 
land. 

B.  fuscus  Krabbe.     Intestine ;  not  rare  in  Iceland. 
"      "     var.  reticulalus  Kr. "       "  " 

""      "     var.  dubiusKr.          "       "  " 

Dibothrium  serratum  Diesing.     Intestine  ;  very  rare. 

TREMATODES. 

Holostoma  alatum  Nitzsch.     Intestine  ;  less  common  than  in 
the  fox. 

NEMATODES. 

Trichina    spiralis    Owen.      Intestine    (mature) ;    larvae    in 

muscles. 
Spiroptera  sanguinolenta  Rudolphi.  (Esophagus,  stomach,  and 

heart,  larvae  in  blood  ;  very  common  in  China. 
Irichosoma  plica  Rudolphi.     Bladder  ;  rare. 
Trichocephalus  depressiusculus  Rud.     Coecum  ;    not  common. 
Ascaris  marginata  Rud.     Small  intestine  ;  very  common. 
Pseudalius  filum   Duj.(?).      Heart  and  pulmonary  artery, 

recorded  by  Collas  ;  originally  from  porpoise. 
Eustrongylm  gigas  Diesing.     Kidney  ;  rare. 
Dochmius   trigonocephalus  Duj.     Intestine,  larvae  in  water ; 

rare. 

Filaria  trispinulosa  (larval  form) .    Eye. 
F.  sanguinis  (larval  form).     In  blood. 
F.  immitis  Leidy.     Heart. 


PARASITES   OP   ANIMALS.  63 

Dracunculus  medinensis  Cobbold.     Sub-cutaneous  tissues  ;  in 
tropical- Asia,  Africa,  and  America. 

ACARINA. 

Pentastoma  tcenioides  Rudolphi.     Nostrils ;  not  rare.     Larvae 

in  man  and  cattle. 

That  thousands  of  lambs  and  sheep  are  annually  killed  by 
dogs  that  have  a  taste  for  mutton  of  their  own  procuring  is 
unfortunately  too  well  known  to  most  of  the  farmers  in  this 
country,  especially  in  those  States  where  neither  stringent 
laws  nor  severe  taxes  have  diminished  the  numbers  of  these 
useless  curs. 

That  the  number  of  dogs  in  every  part  of  the  country  is  by 
far  too  great,  and  even  dangerously  so,  is  generally  admitted, 
especially  during  the  summer,  when  mad  dogs  and  hydropho- 
bia are  the  constant  theme  of  conversation  in  our  cities.  That 
the  laws  of  every  State  ought  to  impose  restrictions,  or,  at 
least,  very  high  taxes  upon  the  owners  of  dogs  is  evident  and 
advocated  by  many  legislators.  Yet  it  is  not,  by  any  means, 
generally  known  to  what  an  alarming  extent  our  flocks  are  in- 
jured in  health  and  depreciated  in  value  by  the  parasites  de- 
rived directly  from  dogs.  Still  less  is  it  known  to  what  an 
extent  human  lives  and  health  are  sacrificed  on  account  of 
these  animals. 

There  are  three  principal  and  very  important  parasites  of 
sheep  derived  from  tape-worms  of  dogs.  These  are  :  1.  The 
"  water-brain"  of  sheep,  which  is  produced  by  the  young  or 
larvas  of  a  small  tape-worm  (Tcenia  ccenurus)  ;  2.  The  ech- 
inococcus,  or  hydatid  tumors  of  sheep,  of  cattle,  and  of  man, 
found  Jn  various  organs,  but  most  commonly  in  the  liver, 
brain,  and  kidneys,  which  are  caused  by  the  young  of  a  very 
small  dog  tape-worm  (Tcenia  echinococeus)  ;  3.  The  diving 
bladder-worm,  or  u  water-bladder,"  often  found  in  the  abdo- 
men of  sheep,  cattle,  and  pigs,  frequently  forming  tumors  as 
large  as  a  hen's-egg,  or  even  a  goose-egg,  which  is  the  young 
of  a  larger  tape-worm  of  the  dog  (Tcenia  marginata).  There 
are,  also,  others  of  less  importance  obtained  by  sheep  from 
dogs,  as  indicated  in  the  lists. 


64  BOARD   OF   AGRICULTURE. 

It  is  perfectly  safe  to  say  that  at  least  twenty-five  sheep  are 
killed  by  parasites  derived  from  dogs,  for  every  one  killed  by 
the  teeth  of  dogs  !  It  is  also  safe  to  say  that  more  than  fifty 
persons  die  from  the  same  parasites,  for  every  one  that  dies  of 
hydrophobia !  And  yet  this  work  of  destruction  goes  on 
silently  and  almost  unobserved,  except  by  professional  men 
week  after  week  and  year  after  year.  The  loss  of  human  life 
every  year  more  than  counterbalances  all  the  good  that  all  the 
dogs  in  the  civilized  world  can  possibly  do.  In  Iceland  it  is 
stated  that  one-sixth  of  all  the  deaths  are  caused  by  one  of 
the  dog-parasites  (EchinococcMs) .  The  same  parasite  occurs 
also,  not  unfrequently,  in  all  other  parts  of  the  world  where 
dogs  are  kept,  and  causes  most  horrible  disease  and  death. 
To  this  we  may  add  the  Pentastoma^  which  man  also  derives 
from  dogs,  and  in  all  probability  several  other  parasites,  in- 
ternal and  external. 

INTERNAL  PARASITES  OF  THE  CAT. 

CESTODES. 

Tcenia   crassicollis  Rud.     Intestine,  young  in  rats  and  mice. 
T.  elliptica  Batscli.     Small  intestine  ;  common. 
T.  canis-lagopodis  Rud.     Intestine  ;  common  in  Iceland. 
Dibothrium  dedpiens    Diesing.      Intestine,  also  in   leopard, 
ounce,  etc.     Perhaps  Bothriocephalus  felis  Creplin. 

TREMATODES. 

Amphistoma  truncatum  Rud. 

Distoma  lanceolatum  Mehlis.     Bile  ducts  ;  rare. 

NEMATODES. 

Trichina  spiralis  Owen.     Intestine,  young  in  muscles. 
Dochmius  tubceformis  Dujadin.     Duodenum. 
Ollulanus  tricuspis  Leuck.     Intestine,  and  young  in  muscles. 
Ascarismystax  Rud.     Small  intestine  ;  common. 

ACARINA. 

Pentastoma  denticulatum  Rud.     Cysts  on  liver,  etc. 

This  list  includes  all  those  that  I  have  found  recorded  from 
the  house  cat,  but  doubtless  many  others  may  occur. 


PARASITES    OF    ANIMALS. 

INTERNAL  PARASITES  OF  SHEEP. 


65 


CESTODES. 

Tcenia  expansa  Rud.     Mature,  in  small  intestine. 

Tcenia.  (Undetermined  species  with  hooks.)  In  cysticercus 
state  in  muscles. 

T.  marginata  Batsch.  Young  or  cysticercus  state  in  viscera, 
adult  in  dog  ;  common. 

T.  coenurm  Kuch.  Young  or  encysted  state  in  large  tumors 
in  the  brain,  adult  in  dog  ;  common. 

T.  echinococctts  Siebold.  Young  or  hydatid  condition  in  liv- 
er, lungs,  brain,  and  other  organs,  adult  in  dog  ;  common. 

TREMATODES. 

Fasciola  Jiepatiea  Linn.     Liver  and  bile  ducts. 
Distoma  lanceolatum  Mehlis.     Bile  ducts. 
Ampkistoma  conicum  Rud.     First  stomach. 

NEMATODES. 

Ascaris  ovis  Rudolphi.     Intestine  ;  rare. 
Trichocephalus  ovis  (affinisf).     Large  intestine  ;  common. 
Sclerostoma  hypostomum  Dujadin.     Intestine. 
Strongylus  contortus  Rud.    Small  intestine. 
S.  filicollis  R,ud..     Small  intestine.     Perhaps  same^  as  last. 
S.  filaria  Rud.     Trachea  and  bronchial  tubes ;  common  ;  also 
in  the  goat. 

ACARINA. 

Pentastoma  tcenioides  Rud.     Larynx,  nostrils,  etc. 

The  goat  is  infested  by  many  of  the  parasites  found  in 
sheep.  Besides  these,  there  are  a  few  peculiar  species; 
among  them  are  Tcenia  caprce  and  Strongylus  venulosus  Ru- 
dolphi, both  found  in  the  intestine. 

INTERNAL  PARASITES  OF  CATTLE. 

CESTODES. 

Tcenia  expansa  Rudolphi.     Intestine,  mature  ;  not  common. 
T.  denticulata  Rud.     Intestine,  mature  ;  rare. 
T.  mediocanellata  Kiich.     Young  or  cysticercus  state  in  mus- 
cles, adult  in  man  ;  common. 
9 


66  BOARD   OF    AGRICULTURE. 

T.  marginata  Batsch.     Young  or  cysticercus  state  in  viscera, 

adult  in  dog ;  common. 
T.  echinococcus  Siebold.      Young  or  hydatid  state   in  liver, 

brain,  and  various  other  organs,  adult  in  dog  ;  common. 
T.  coenurus  Kiich.    Young  state  in  brain,  adult  in  dog ;  rare. 

TREMATODES. 

Fasciola  Tiepatica  Linn.      Liver,  gall-ducts,  etc.;  not  rare. 
Distoma  lanceolatum    Mehlis.     Liver  ;  not  uncommon. 
Amphistoma  conicum  Rud.      First  stomach  ;  common. 
A.  crumeniferum  Creplin.     Stomach. 
A.  explanatum  Creplin.     Bile  ducts. 

NEMATODES. 

Trichina  spiralis  Owen.      Observed  only  in  experimental  an- 
imals. 

Trichoceplialus  affinis  Rud.     Large  intestine ;  frequent. 
Strongylus  radialus  Rud.      Duodenum,  colon,  small  intestine. 
S  micrurus  Mehlis.     Trachea  and  bronchial  tubes. 
Eustrongylus  gigas  Diesing.     Kidney  ;  rare. 
Filaria  lachrymalis  Gurlt.     Lachrymal  ducts,  etc. 
F.papillosa  Rudolphi.     Abdominal  cavity,  etc.;  rare. 

ACARTNA. 

Pentastoma  tcenioides  Rud.     Nasal  cavaties,  larynx,  etc. 
P.  denticulatum  Rud.      (Young  of  preceding.)     In  cysts  on 
liver,  etc. 

INTERNAL  PARASITES  OF  THE  HORSE. 

CESTODES. 

Tcenia  perfollata    Goeze.      Swell  intestine,   colon,   ccecum ; 

common,  and  sometimes  in  vast  numbers. 
T.  plicata   Rud.     Stomach  and  small  intestine  ;  common. 
T.  mamillana   Mehlis.    Large  intestine  ;  common. 
Tcenia,   (species  undetermined).      Young   state  {cysticercus 

fistularis)  in  peritoneum. 

T.  coenurus  Kuch.     Young  or  encysted  state  in  brain  ;  rare. 
T.  echinococcus  Siebold.       Hydatid   state  in  liver,  etc.;  not 

common. 

TEMATODES. 

Fasciola  hepatica  Linn.     Liver,  gall-bladder,  etc. 


PARASITES  OP  ANIMALS.  67 

NEMATODES. 

Ascaris  megalocephala  Cloquet.  Small  intestine  ;  common. 

Oxyuris  curvula  Rudolphi.    Colon,  coecum,  rectum  ;  common. 

Eustrongylus  gigas  Diesing.     Kidney,  etc. 

Sclerostoma  equinum  Blainv.  Duodenum,  colon,  coecum,  pan- 
creas, sometimes  very  numerous,  and  in  enlargements  of 
the  arteries;  common. 

S.  tetraoanthum  Diesing.      Duodenum,  ccecum,  .colon. 

Strongylus  micrurus  Mehlis.     Trachea  and  bronchial  tubes. 

Filaria  microstoma  Schneider. 

F.  papillosa  Rud.      Abdomen,  thorax,  brain,  eye,  intestine. 

F.  lachrymal™  Gurlt.  About  the  eyes,  in  lachrymal  ducts,  etc. 

Spiroptera  megastoma  Rud.     Tubercles  in  stomach. 

Dracunculus  medinensis  Cobbold.  (Guinea-worm).  Subcu- 
taneous tissues  ;  only  in  tropical  parts  of  Africa,  Asia,  and 
America. 

ACARINA. 

Pentastoma  tamioides  Rud.     Nasal  cavities,  larynx,  etc. 

The  mule  and  ass  are  subject  to  the  same  parasites  as  the 
horse,  but  not  to  the  same  extent.  The  number  of  species 
hitherto  observed  is  less,  and  they  are  far  less  common. 

INTERNAL   PARASITES  OF  THE  HOG. 

CESTODES. 

Tcenia  solium  Linn.     In  the  larval  or  cysticurcus  state  in  the 

abdominal  viscera. 

T.  marginata  Kiich.  Cysticercus  state  in  the  abdominal  viscera. 
T.  echmococcus  Siebold.     Hydatid  state  in  liver,  etc.;  not 

common. 

TREMATODES. 

Fasciola  hepatica  Linn.     Liver  and  bile  ducts. 
Distoma  lanceolatum  Mehlis.     Bile  ducts. 

ACANTHOCEPHALA. 

Echinorhynchus  gigas  Goeze.     Small  intestine  ;  common. 

NEMATODES. 

Trichina  spiralis  Owen.  Mature  in  intestine,  young  in  mus- 
cles ;  common. 


68  BOARD  OF  AGRICULTURE. 

Ascaris  suilla  Dujardin.  Small  intestine  ;  common. 
Spiroptera  strongs/Una  Rud.     Stomach. 
Simondsia  paradoxa  Cobbold.  Stomach,  in  cysts  ;  one  case. 
Trichocephalus  crenatus  Rud.     Large  intestine. 
Strongylus  dentatus  Rud.    Coecum,  colon. 
S.  elongatus  Dujardin.     Bronchial  tubes. 
S.  paradoxus  Mehlis.     Trachea  and  bronchial  tubes. 
EustrongyluB  gigas  Diesing.    Kidneys,  etc. 
Sclerostoma  pinguicola  Verrill.  In  fat  about  kidneys  and  "spare- 
ribs,"  in  large  numbers  ;  probably  common. 

ACARINA. 

Pentastoma  denticulatum  Rud.     Cysts  on  liver,  etc. 
INTERNAL  PARASITES  OF  POULTRY. 

CESTODES. 

Tcenia    infundibuliformis  Goeze.      Intestine  of  hens,  ducks, 

geese,  etc. 

T.  proglotlina  Davaine.     Duodenum  of  hens  ;  common. 
T.  crassula  Rud.     Intestine  of  pigeons,  hens,  and  geese. 
T.  malleus  Goeze.     Intestine  of  geese  and  ducks,  etc. 
T.  lanceolata  Goeze.   Intestine  of  geese  and  ducks,  etc. 
T.  setigera  Froh.     Intestine  of  geese  ;  common. 
T.  sinuosa  Rud.     Intestine  of  geese  and  ducks. 
T.fasciata  Rud.     Intestine  of  geese  ;  common. 

TREMATODES. 

Monostoma  mutabile  Zeder.    Sub-orbital  cavities  of  geese,  etc. 

M.  variabile.     Geese. 

M.  triseriale.    Geese.     Perhaps  same  as  the  next. 

M.  verrucosum  Zeder.     Ducks,  in  coecum. 

M.  caryophyllinum  Bremser.     Ducks.    Originally    described 

from  fish. 

Distoma  ovatum  Rud.     Oviducts,  etc.,  of  geese  and  ducks. 
D.  linear e  Zeder.    Large  intestine  of  hens. 
D.  dilitatum  Miram.     With  last. 
D.  echinatum  Zeder.     Intestine  of  ducks  and  geese. 
D.  oxycephalum  Rud.     Same  habits  as  last. 

ACANTHOCEPHALA. 

Echinorhynchus  polymorplius  Bremser.     Intestine  of  ducks. 


PARASITES  OF  ANIMALS.  69 

NEMATODES. 

Heterakis  compressa  Schneider.     Intestine  of  chicken. 

If.  vesicularis  Duj.     Intestine  of  hens  and  turkeys. 

H.  dispar  Duj.     Intestine  of  geese. 

Ascaris  crassa  Desl.     Intestine  of  ducks. 

A.  inflexa  Rud.    Intestine  of  hens. 

A.perspicillum  Rud.     Intestine  of  turkey. 

A.  maculosa  Rud.     Intestine  of  pigeon. 

jSpirotera  hamulosa.    Gizzard  of  hens. 

S.  uncinata  Rud.    Tubercles  in  oesophagus  of  geese. 

Syngamus  trachealis   Siebold.     Windpipe,  causing   "gapes.'' 

Strongylus   nodularis   Rud.    Gizzard  and  intestine  of  ducks 

and  geese. 

In  the  preceding  lists  we  have  brought  together  most  of  the 
parasites  hitherto  discovered  in  our  more  common  domestic 
animals.  There  can  be  no  doubt  but  that  many  more  will 
hereafter  be  discovered.  In  the  rabbit,  Guinea-pig,  parrots, 
singing  birds,  and  other  animals  often  domesticated,  many 
additional  species  occur. 

In  the  following  pages  only  the  more  common  and  impor- 
tant species  will  be  described. 

The  Armed  Tape-worm  or  Pork  Tape-worm  of  Man  (Tcenia 
solium  Linn.)  ;  and  its  young,  the  "  measles"  of  pork  and  hu- 
man flesh. 

This  is  perhaps  the  best  known  of  all  the  numerous  kinds  of 
tape-worms.  Its  young  or  larvae  are  common  in  the  muscles 
and  other  organs  of  hogs,  and  not  very  rare  in  man.  (See 
Figures  49-51.)  In  the  adult  stale  it  is,  so  far  as  known,  pe- 
culiar to  the  human  intestine,  where  it  is  unnecessarily  com- 
mon! It  grows  to  a  great  length,  frequently  ten  to  fifteen 
feet,  or  even  more,  and  is  then  composed  of  upwards  of  800 
joints,  those  that  are  sexually  mature  commencing  at  about  the 
450th  segment.  The  head  is  small,  about  the  size  of  a  pin- 
head,  roundish,  with  four  prominent  suckers  on  the  sides,  and 
a  conical,  proboscis-like  top,  around  which  there  are  two  cir- 
cles of  sharp  hooks,  22  to  28  in  each  circle  (Figure  53). 
The  neck  portion  is  slender,  crossed  by  fine  lines,  which  are 
wider  apart  as  they  recede  from  the  head,  finally  forming  dis- 


70 


BOARD    OP   AGRICULTURE. 


tinct  joints.  These  are  at  first  very  small  and  short,  gradually 
becoming  broader  and  squarish,  then  oblong.  The  largest 
are  about  a  third  of  an  inch  in  breadth  and  quite  thin  and  flat 
(Figure  52).  The  sexually  mature  joints  or  proglottides  are 
twice  as  long  as  broad,  and  contain  the  ovaries  and  a  long 
central  egg  cavity  or  uterus,  with  7  to  12  lateral  branches, 
which  are  irregularly  lobed  and  divided  (Figure  54)  ;  and  also 
the  male  organ,  or  testicle,  in  the  form  of  branched  tubes, 
communicating  with  a  penis,  which  is  situated  on  one  edge 
of  the  joint,  in  front  of  the  female  genital  orifice,  and  has  a 
curved  or  sickle-shaped  form.  The  genital  openings  are  either 
on  the  right  or  left  edge  indifferently,  in  the  successive  joints. 

Figure  49.  Figure  52. 


The  young  or  larval  state  produces  the  white  spots  known  as 

Figure 49. — Pork  "  measles"  ;  natural  size;  Hearth  and  Home,  after  Owen. 

Figure  50. — Young  tape  worm  from  measles  of  pork;  and  Fig.  51,  head  of  same, 
more  enlarged ;  Hearth  and  Home,  after  Owen. 

Figure  52. — Pork  tape-worm  (Tcenia  solium),  less  than  natural  size ;  Hearth  and 
Home,  after  Owen. 


PARASITES    OP   ANIMALS. 


71 


/  measles  "  in  pork  (Figure  49)-.  These  are  cavities  or  cysts 
produced  by  inflammation,  containing  whitish  fluid  and  enclos- 
ing small,  bladder-like,  translucent,  vesicles,  filled  with  a  watery 
fluid,  and  which  contain  the  proper  head  and  neck  of  the  young 
worm  coiled  up  spirally  in  the  interior  in  an  inverted  position. 
By  gentle  pressure  the  head  and  neck  may  be  made  to  protrude 
by  inversion,  like  the  finger  of  a  glove,  and  will  then  present 
the  appearance  shown  in  figure  50,  the  vesicle  of  fluid  now 
forming  the  flask-like  caudal  portion  of  the  worm.  The  head 
may  now  be  seen  to  have  four  suckers  and  a  central  promi- 
nence surrounded  by  two  circles  of  hooks,  as  in  the  adult.  In 
this  condition,  enclosed  in  the  cysts,  they  will  remain  living 

Figure  53.  Figure  54. 

V 


for  a  long  time  in  the  hog,  even  surviving  the  death  of  their 
host  for  a  considerable  period.  If  one  or  more  of  these  young 
worms  or  measles  be  swallowed  by  a  human  being,  the  mus- 
cular fibres  and  the  cysts  will  be  digested,  and  each  young 
worm  thus  liberated  will  evert  its  head,  and  losing  its  bladder- 
like  portion,  will  pass  into  the  intestine.  There  it  will  fasten 
itself  to  the  inner  membrane  by  its  suckers  and  hooks,  and 
grow  rapidly  by  absorbing  the  digested  food  by  which  it  is 
surrounded.  New  joints  will  be  rapidly  formed  as  the  older 
ones  grow  larger,  until  it  becomes  a  mature  tape-worm,  with 
joints  ready  to  be  cast  off.  There  may  be  but  one  tape-worm  in 

Figure  53.     Head  of  Tcenia  solium,  magnified.    From  Cob  bold. 
Figure  54. — A  joint  or  proglottis  of  Tcenia  solium,  magnified  ;  a,  branches  of  the 
uterus  ;  &,  external  orifice  ;  c,  male  organ.     From  Cobbold. 


72  BOARD  OF  AGRICULTURE. 

the  human  intestine,  or  there  may  be  several  together,  the 
number  depending  only  upon  the  number  of  living  young- 
swallowed. 

It  is,  therefore,  obvious  that  this  tape-worm  can  be  acquired 
only  by  eating  raw  or  under-done  pork.  In  this  country  the 
principal  kinds  of  food  serving  as  sources  of  this  tape-worm 
are  raw  smoked  ham  and  raw  sausages,  but  soldiers  and  others 
are  often  obliged  to  eat  their  pork-rations  uncooked,  and  thus 
obtain  the  parasites.  Our  recent  war  was  the  means  of  greatly 
increasing  the  numbers  of  this  and  other  parasites,  both  in- 
ternal and  external. 

Persons  harboring  the  mature  tape-worms  become  in  their 
turn  the  means  of  diffusing  the  race.  Each  mature  joint  cast 
off  contains  several  thousands  of  eggs,  each  of  which  encloses 
an  embryo,  nearly  ready  to  hatch,  and  as  these  joints  are  con- 
tinually being  discharged  during  the  whole  life  of  the  worm, 
which  may  be  ten  or  twelve  years,  it  is  evident  that  one  per- 
son may  thus  be  the  means  of  diffusing  many  millions  of  eggs, 
most  of  which  will  no  doubt  perish,  but  the  chances  are  good 
that  some  of  them  will  find  their  way  into  the  stomachs  of 
hogs,  either  with  their  food  or  in  water. 

The  free  joints  or  proglottides  have  an  independent  life  for 
a  few  days  and  are  capable  of  moving  and  crawling  about  to 
a  considerable  extent.  In  a  short  time,  however,  the  myriads 
of  embryos  in  the  interior  so  increase  in  size  that  the  walls  of 
the  proglottis  burst  open  and  thus  liberate  the  eggs.  The 
eggs  are  globular  and  very  small,  their  average  diameter 
being  about  ^4  of  an  inch ;  the  shell  is  comparatively 
thick,  being  s^W  of  an  inch.  They  are  so  small  that  they 
may  be  blown  about  by  the  winds,  carried  on  the  feet  of  in- 
sects, or  may  be  suspended  in  unfiltered  waters.  They  may, 
therefore,  also  readily  adhere  to  lettuce,  celery,  and  other 
garden  plants,  or  to  fallen  fruit,  especially  when  night-soil  is 
used  as  manure,  and  unless  such  food  be  carefully  and 
thoroughly  washed,  there  is  always  more  or  less  danger  of 
eating  the  eggs  of  this  and  other  parasites.  When  these  eggs 
are  swallowed,  either  by  hogs  or  human  beings,  they  hatch  as 
soon  as  acted  upon  by  the  gastric  juice,  and  disclose  their  con- 


PARASITES  OP  ANIMALS.  73 

tained  embryos,  which  are  very  different  from  both  the  old 
worm  and  the  measle-worm.  They  are  provided  with  six 
hooks  or  spines,  placed  in  three  pairs  upon  the  head.  By 
means  of  these  they  quickly  bore  their  way  through  the  walls 
of  the  intestine  into  the  blood-vessels,  and  are  thus  carried  to 
all  parts  of  the  body.  They  finally  lodge  in  various  organs, 
but  especially  in  the  muscles,  liver,  brain,  eyes,  lungs,  and 
heart.  They  then  excavate  galleries  for  themselves  in  these 
situations,  causing,  if  in  large  numbers,  a  great  amount  of 
inflammation  and  disease,  which  in  some  cases  proves  fatal. 
The  inflammation  soon  causes  cysts  to  be  formed  around  the 
intruders,  by  which  they  are  enclosed  and  restricted  in  their 
motions.  Thus  the  "  measles"  in  the  muscles  of  hogs  and 
man  are  formed.  After  this  the  patient  may  recover,  unless 
these  parasites  have  lodged  in  the  brain  or  other  vital  organs,  so 
as  to  produce  serious  symptoms  subsequently.  In  the  human 
subject  more  than  100  cases  have  been  recorded  in  which 
these  parasites  have  taken  up  their  abode  in  the  brain,  causing 
epilepsy,  insanity,  and  sometimes  sudden  death.  In  such 
cases,  which  are  probably  more  common  than  is  generally  im- 
agined, there  can  be  no  relief.  There  have  also  been  recorded 
quite  as  many  instances  in  which  these  cysticerci  or  larval  tape- 
worms have  been  situated  within  the  ball  of  the  eye,  causing 
a  partial  or  total  loss  of  sight,  and  sometimes  great  inflamma- 
tion. Many  of  these  have  been  successfully  removed.  In 
other  important  organs  they  are  liable  to  produce  serious 
trouble.  But  when  in  the  subcutaneous,  areolar,  or  inter- 
muscular  tissues,  they  may  often  be  easily  removed  by  the 
surgeon.  In  hogs  they  are  much  more  liable  to  produce  these 
results,  because  hogs  are  likely  to  swallow  whole  joints,  or 
even  entire  tape-worms,  while  human  beings  seldom  swallow 
more  than  a  few  dozens  of  eggs. 

The  effects  and  symptoms  caused  by  the  adult  tape-worms 
are  discussed  under  the  next  species,  together  with  the 
remedies. 

As  means  of  prevention  every  one  should  avoid  eating  pork, 
in  any  form,  that  has  not  been  .thoroughly  cooked.     In  this 
way  it  is  easy  to  avoid  the  mature  tape-worm  of  this  species. 
10 


74  BOARD   OF   AGRICULTURE. 

To  prevent  measles  in  hogs  they  should  not  be  allowed  to  have 
access  to  human  excrement,  the  reverse  of  which  is  too  often 
specially  provided  for  by  farmers.  To  avoid  the  same  para- 
sites in  our  own  flesh  we  must  take  care  to  have  all  fruit  and 
other  uncooked  vegetable  food  well  washed  and  our  drinking 
water  pure. 

The  Beef  Tape-worm  of  Man  (Tcenia,  mediocanellata  Kuch.)  ; 
and  its  young,  the  "  measles"  of  veal  and  beef. 

This  is  a  very  large  species,  which  was  formerly  generally 
known  as  the  unarmed  variety  of  the  human  tape-worm.  It 
is  known  to  occur  among  all  beef-eating  people,  and  is  the 
common  species  in  Africa,  Western  Asia,  and  several  European 
countries,  especially  in  Austria,  Turkey,  and  certain  parts  of 
Russia. 

It  has  long  been  known  that  Jews,  Mohammedans,  and  other 
people  who  never  eat  pork,  are  nevertheless  liable  to  be  in- 
fested by  tape-worms.  It  was  also  observed,  many  years  ago, 
that  infants  fed  upon  dried  beef — a  custom  much  practised  at 
St.  Petersburg — were  liable  to  have  the  same  parasites  ;  and 
these  facts  were  formerly  brought  forward  as  arguments 
against  the  doctrine  that  the  common  tape-worm  is  derived 
from  eating  the  larval  form  contained  in  measly  pork.  BUG 
it  was  soon  discovered  that  nearly  all  the  tape-worms  obtained 
from  patients  in  Mohammedan  countries,  as  well  as  in  Austria, 
and  some  other  parts  of  Europe  where  pork  is  little  used,  were 
destitute  of  the  two  circles  of  peculiar  hooks  around  the  cen- 
tral, proboscis-like  prominence  of  the  head,  as  well  as  the 
prominence  itself,  which  are  very  conspicuous  features  in  the 
common  tape-worm  of  pork-eating  people.  Owing  to  these 
peculiarities,  naturalists  began  to  consider  the  two  forms 
either  as  different  varieties  or  different  species.  The  source 
of  the  unarmed  tape-worm  remained  uncertain,  however,  until 
direct  experiments  were  undertaken  by  Leuckart,  Mosler,  and 
others  to  settle  this  question.  Thus  it  was  discovered  that 
when  the  joints  or  eggs  of  the  unarmed  tape-worm  ( Tcenia 
mediocanellata)  were  given  to  calves,  the  eggs  hatched  in  the 
stomach,  and  the  young  embryos  worked  their  way,  by  means 


PARASITES   OP   ANIMALS.  75 

of  their  six  boring  hooks,  through  the  intestine  into  the  cir- 
culation and,  lodging  in  the  muscles,  caused  serious  disease 
or  death,  if  in  too  large  numbers,  and  after  a  time  became 
enclosed  in  little  capsules,  producing,  in  fact,  "  measly"  veal 
or  beef,  as  shown  in  Figure  55,  which  represents  part  of  a 
muscle  of  the  hind  leg  from  a  calf  that  had  been  fed  by  Drs. 
Cobbold  and  Simonds  upon  the  eggs  of  this  tape-worm,  and 
killed  three  months  afterward.  The  flesh  of  this  calf  was 
estimated  to  contain  over  eight  thousand  measles,  and  yet, 
although  at  first  it  had  been  seriously  ill  from  the  effects  of 
the  parasites,  it  was  at  the  time  when  slaughtered  perfectly 

Figure  55.  Figure  56. 


healthy  and  fat.  The  measles  of  veal  or  beef  are  much 
smaller  than  those  of  pork,  and  if  they  existed  only  in 
moderate  numbers,  would  scarcely  be  detected  either  by  the 
butchers  or  consumers.  They  are  seldom  larger  than  a  small 
pea.  One  of  these  u  measles,"  when  examined  with  the 
microscope,  is  found  to  consist  of  an  outer  oval  cyst  or  mem- 
branous sac,  enclosing  loosely  in  its  cavity  a  more  delicate 
vesicle  filled  with  fluid  and  containing  the  inverted  head  of 
the  young  tape-worm,  as  represented  in  Figure  56.  The  head 
has  four  well-marked  suckers,  but  has  no  central  proboscis 
and  no  circle  of  hooks — differing  therefore  from  the  pork- 
measle,  or  cysticercus,  in  just  the  same  way  that  the  heads  of 
the  mature  tape-worms  differ  from  each  other.  Thus  it  was 
definitely  settled  that  the  unarmed  or  bookless  tape-worm  of 

Figure  55. — Measles  in  veal,"reduced.     Hearth  and  Home,  after  Cobbold. 
Figure  56. — One  of  the  measles  magnified.    Hearth  and  Home,  after  Cobbold* 


76 


BOARD   OP  AGRICULTURE. 


man  (  Tcenia  mediocanellata)  is  obtained  by  eating  the  young, 
in  the  shape  of  "measles,"  in  raw  or  slightly  cooked  beef  and 

Figure  57.  Figure  58. 


Figure  59. 


veal.     And  thus  the  presence  of  tape-worms  in  infants  fed  on 
dried  beef,  as  well  as  in  Jews  and  others  not  guilty  of  eating 

Figure  57. — Tcenia  mediocanellata,  natural  size.  Hearth  and  Home,  after 
Leuckart. 

Figure  58. — Head  of  beef  tape- worm,  magnified.  Hearth  and  Home,  after 
Leuckart. 

Figure  59. — A  joint  of  the  beef  tape-worm,  showing  the  ovaries,  enlarged.  Hearth 
arid  Home,  after  Leuckart. 


PARASITES  OP  ANIMALS.  77 

pork,  is  fully  explained.  Since  these  facts  have  been  ascer- 
tained, search  has  been  made  for  "  measles"  in  beef  from 
animals  not  experimented  upon,  and  they  have  been  found  in 
several  instances. 

When  such  beef  is  swallowed  by  man,  without  cooking,  the 
young  tape-worms  are  liberated  from  their  capsules  or  cysts 
by  the  process  of  digestion  ;  the  head  becomes  protruded,  and, 
passing  into  the  intestine,  it  fastens  upon  the  lining  mem- 
brane by  its  suckers.  There  it  rapidly  grows  larger,  new 
joints  are  developed,  and  the  body  grows  longer  and  longer, 
the  form  of  the  joints  changing  as  they  grow,  until  those  that 
are  most  mature  become  square,  and  finally  oblong,  as  shown 
in  Figure  57,  which  represents  a  beef  tape-worm,  of  natural 
size,  in  several  sections,  the  intermediate  joints  being  omitted. 
When  full  grown,  which  requires  three  or  four  months,  one  of 
these  tape-worms  may  contain  over  800  joints,  of  which  860 
to  400  of  the  last  ones  will  be  sexually  mature,  each  one  con- 
taining 5000  or  more  eggs.  This  species  is  much  larger  than 
the  pork  tape-worm  (T.  solium},  as  well  as  longer,  its  length 
being  sometimes  twenty  feet,  and  its  greatest  breadth  half  an 
inch,  while  the  joints  are  thicker  and  stouter,  or  have  a  plump 
look,  instead  of  being  thin  and  flat,  as  in  the  other.  The 
head,  as  already  intimated,  is  quite  different  in  the  two  species 
— that  of  the  beef-worm  being  larger  and  flat,  or  even  concave, 
at  the  end,  with  four  large  suckers  on  the  sides,  as  shown, 
greatly  magnified,  in  Figure  58.  The  joints  themselves  are 
very  different  internally,  the  egg-masses  or  uteri  being  very 
numerous,  and  crowded  together  in  a  more  parallel  manner 
(Figure  59)  in  this  than  in  the  pork  tape-worm,  in  which 
they  are  fewer  and  more  aborescently  branched.  The  mature 
joints,  filled  with  eggs,  are  cast  off,  as  in  other  tape-worms, 
and  leaving  the  intestine,  have  an  independent  existence  for 
a  few  days,  when  they  burst  by  the  enlargement  of  the  embryos 
in  the  eggs.  The  eggs  are  thus  scattered  about  in  manure,  in 
water,  in  the  drainage  of  cess-pools  and  sewers,  by  the  winds, 
and  by  insects.  It  is  not  strange,  therefore,  that  cattle  should 
occasionally  swallow  such  eggs  with  their  food  and  drink, 
especially  if  we  reflect  that  one  man,  harboring  only  one  of 


78  BOARD   OF   AGRICULTURE. 

these  worms,  may  thus  scatter  about,  during  a  single  year, 
more  than  a  thousand  joints,  and  if  each  of  these  contains  but 
5000  eggs,  he  would  thus  diffuse  5,000,000  eggs,  each  con- 
taining an  active  embryo,  ready  to  leave  its  shell  the  moment 
that  it  enters  the  stomach  of  a  calf,  cow,  or  ox.  Young  ani- 
mals seem  to  be  more  liable  to  be  infected  by  them  than  old 
ones.  Fortunately  these  young  worms  retain  their  vitality 
for  but  one  year  when  enclosed  in  the  flesh,  and  after* that 
die  and,  withering  away,  leave  only  a  very  small  yellowish 
spot,  containing  calcareous  particles.  The  adult  worm,  if 
left  undisturbed,  will  live  in  a  person  ten  or  twelve  years, 
constantly  dropping  its  joints.  Among  the  Burates,  or  Cos- 
sacks of  ihe  Baikal  region,  this  species  is  very  abundant. 
Their  habits  of  eating  chiefly  the  raw  or  slightly  cooked  flesh 
of  cattle,  sheep,  camels,  horses,  and  goats,  while  they  devour 
the  liver,  kidneys,  and  fat  quite  raw,  would  lead  us  to  expect 
that  this  and  other  parasites  might  abound  in  their  bodies, 
which  proves  to  be  the  case.  According  to  Dr.  Kaschin  in  130 
post  mortem  examinations  only  two  bodies  were  found  with 
out  this  tape-worm,  and  among  500  hospital  patients  every 
one  had  it.  Sometimes  as  many  as  fifteen  specimens  were 
found  in  one  person. 

It  has  been  supposed  until  within  a  short  time  that  the 
beef  tape-worm  (Tcenia,  mediocanellata)  was  very  rare  in 
Great  Britain  and  the  United  States,  where  the  pork  tape- 
worm was  thought  to  be  the  only  one  that  was  at  all  common 
in  man.  Dr.  Cobbold  has  shown,  however,  in  his  late  works 
on  parasitic  worms,  that  the  beef  tape-worm  is  really  quite  as 
common  in  England  as  the  pork  tape  worm,  the  wealthier 
classes  generally  harboring  the  former,  and  the  poorer  people 
the  latter.  I  am  convinced  that,  even  if  not  so  common  as 
the  pork  tape-worm,  the  beef  tape-worm  is  by  no  means  so 
rare  in  America  as  is  generally  supposed.  The  Museum  oi 
Yale  College  possesses  one  large  specimen,  raised  by  a  citizen 
of  New  Haven,  and  many  other  museums  in  the  United  States 
no  doubt  contain  them,  labelled,  however, "  Tceniq  solium."  In 
fact,  probably  not  one  physician  in  a  thousand,  in  the  country 
at  large,  possesses  the  knowledge  of  the  subject  requisite  for 


PARASITES   OF    ANIMALS.  79 

distinguishing  the  two  species   and,  therefore,  both  are  con- 
founded together  as  "  the  common  tape-worm." 

In  this  country  persons  generally  obtain  this  parasite  by 
eating  dried  beef  and  Bologna  sausages  uncooked.  In  the  lat- 
ter, there  may  be  not  only  the  young  of  this  tape-worm,  but 
also  those  of  the  pork  tape-worm  and  Trichina,  since  there  is 
also  an  admixture  of  pork.  It  is  therefore  evident  that  it  is 
unsafe  for  the  individual,  and  even  a  wrong  to  the  community 
for  persons  to  indulge  in  eating  raw  meats  of  any  kind,  for 
we  find  that  pork,  beef,  and  mutton  may  each  contain  the 
young  of  different  tape-worms  and  other  parasites,  and  per- 
sons who  harbor  these  worms  in  their  own  bodies  become,  in 
one  sense,  a  nuisance,  since  they  thus  serve  as  the  propaga- 
tors and  disseminators  of  parasites.  And  although  one  or 
two  of  these  tape-worms  may  not  cause  any  serious  trouble  in 
the  bowels  of  one  man,  in  another  they  may  produce  very 
grave  consequences,  and  still  more  so,  if,  as  often  happens, 
several  live  together  in  one  person. 

Symptoms. 

The  symptoms  and  treatment  are  the  same  for  both  species 
of  human  tape-worms,  but  the  species  now  under  considera- 
tion is  said  to  be  more  easily  destroyed  than  T.  solium,  per- 
haps because  it  does  not  have  so  secure  an  anchorage  as  the 
latter  has,  with  its  hooks  well  imbedded  in  the  membranes. 

The  symptoms  vary  greatly,  according  to  the  temperament 
and  other  peculiarities  of  the  person  affected.  Sometimes  it 
causes  little  or  no  marked  disturbance  of  the  health,  though 
causing  perhaps  more  or  less  weakness,  lassitude,  and  sense  of 
weariness,  often  accompanied  by  restlessness,  nervous  irritabil- 
ity, and  headache,  which  are  nearly  always  attributed  to  other 
causes.  In  more  severe  cases,  these  symptoms  become  much 
increased,  the  headache  especially,  which  is  often  accompa- 
nied by  giddiness.  "  The  sight  and  hearing  may  be  affected  ; 
noises  in  the  head,  itchings  at  the  nose  and  anus,  obscure 
pains  about  the  body  and  limbs,  loss  of  appetite,  -and  other 
dyspeptic  symptoms,  show  themselves  in  greater  or  less  de- 
gree in  different  cases.  One  of  the  most  common  symptoms, 
however,  which  I  have  noticed,  is  the  tendency  to  faintness. 
This  is  sometimes  so  marked  as  to  create  much  alarm,  and  a 


80  BOARD  OF  AGRICULTURE. 

person  uninformed  as  to  the  true  cause  of  the  disorder  might 
be  led  to  treat  the  symptom  as  arising  from  a  totally  different 
source.  In  female  patients  the  nervous  symptoms  display 
features  more  or  less  peculiar  to  the  sex.  The  restlessness 
and  anxiety  are  excessive,  and  at  times  accompanied  by  cho- 
rea and  fits  of  hysteria.  In  the  worst  cases,  in  both  sexes, 
the  cerebral  disturbance  may  show  itself  in  convulsions  and 
epileptiform  seizures.  I  regret  to  have  to  add  that  in  not  a 
few  instances  even  mania  itself  has  been  entirely  attributable 
to  the  presence  of  tape-worms  in  the  intestinal  canal."  Such 
are  the  usual  symptoms,  according  to  Dr.  Cobbold.  Many  un- 
usual and  remarkable  cases  are  on  record.  In  one  instance, 
mania  of  eight  years  duration  was  completely  cured  by  the 
removal  of  the  parasite.  In  another,  hysteria  was  caused  by 
eighteen  tape-worms  in  one  patient.  Many  cases  of  insanity, 
due  to  this  cause,  arc  also  on  record.  The  best  and  perhaps 
only  sure  evidence  of  tape-worms  is  the  passage  of  the  joints 
from  the  intestine. 

Remedies. 

The  remedies  for  tape-worms  are  numerous  and,  if  fresh 
and  pure  drugs  be  used,  there  are  several  that  appear  to  be 
perfectly  reliable  in  most  cases.  These  remedies  should,  how- 
ever, be  administered  with  proper  precautions.  Therefore,  pa- 
tients afflicted  in  this  way  should  immediately  place  them- 
selves under  the  care  of  a  reliable  and  competent  physician. 

The  remedies  chiefly  used  are  the  oil  or  root  of  male-fern, 
kousso,  kamala,  oil  of  turpentine,  panna,  pumpkin-seeds,  and 
pomegranate-root  bark.  These  are  generally  administered 
while  the  patient  fasts.  The  pumpkin-seeds  are  perhaps  the 
most  domestic  remedy,  as  well  as  one  of  the  best,  and  safest  in 
the  hands  of  inexperienced  persons.  The  fresh  seeds  may  be 
bruised  or  pounded  in  a  mortar,  and  mixed  with  water  into  a 
paste,  of  which  the  patient  may  eat  freely,  morning  and  even- 
ing, at  the  same  time  fasting,  or  eating  sparingly  soups  or  similar 
food.  The  root  of  the  male-fern  (Aspidium  filix  mas)  is  gen- 
erally regarded  as  the  most  certain  remedy,  if  fresh  and  pure. 
The  dose  for  an  adult  is  ten  to  fifteen  grammes  of  the  powder, 
morning  and  evening,  followed  by  a  purgative.  The  etherial 


PARASITES  OP  ANIMALS.  81 

extract  is  generally  more  effectual,  however.  The  patient 
should  have  a  sparing  diet  of  soup,  etc.,  for  twelve  or  fifteen 
hours  before  taking  the  medicine,  and  the  second  dose  should 
be  followed,  after  an  hour  or  two,  by  a  purgative  like  castor- 
oil.  These  remedies  are  mentioned  here  not  to  encourage 
self-treatment,  but  for  the  benefit  of  those  who  may  not  be 
within  reach  of  a  reliable  physician. 

The  margined  Tape-worm  of  the  Dog  (Tcenia  marginata 
Batsch)  ;  and  its  young,  the  "  diving  bladder-worm  "  of 
Sheep  and  Cattle. 

The  young  of  this  parasite  are  very  frequently  found  in  the 
abdominal  cavity  of  sheep,  either  attached  to  various  parts  of 
the  viscera,  especially  the  liver  and  mesentery,  or  else  nearly 
or  quite  free  among  the  organs,  so  that  when  the  sheep  are 
opened,  the  bladder-like  sacs  fall  out,  of  their  own  accord. 
These  are  usually  known  to  butchers  as  "  water-bladders." 
When  attached  to  the  organs,  these  bladders  or  sacs  are  usu- 
ally enclosed  in  a  cyst  or  membrane,  formed  by  the  inflamma- 
tory action  that  they  cause.  The  sac  is  soft  and  whitish,  en- 
closing a  watery  fluid,  and  varies  in  size  from  that  of  a  pig- 
eon's egg,  or  less,  to  that  of  a  child's  head ;  but  it  is  rather  un- 
common to  find  them  larger  than  a  hen's  egg.  In  form  they 
are  often  globular,  but  more  frequently  pear-shaped,  as  repre- 
sented in  Figure  60.  If  one  of  these  bladders,  while  still  en- 
closed in  its  cyst,  be  placed  in  a  plate  of  warm  water  and  care- 
fully examined  in  a  good  light,  there  may  be  dimly  seen  in  the 
interior,  near  the  upper  end,  the  outlines  of  the  head  and  neck, 
which  are  turned  inward,  as  usual  in  most  young  tape-worms ; 
but  what  is  singular  in  this  case,  the  head  and  neck  alternately 
rise  and  sink  in  the  fluid  of  the  interior,  with  remarkable  reg- 
ularity. From  this  peculiarity  it  lias  received  the  name  of 
"  diving  blacbder-worm."  This  motion  is  produced  by  a  pe- 
culiar arrangement  of  muscular  fibres  in  the  interior,  which 
are  attached  to  the  neck.  At  the  top  of  the  little  knob  on  the 
upper  end  of  the  bladder  there  is  a  small  slit,  from  which,  by 
gentle  pressure,  the  neck  may  be  gradually  forced  out,  so  as 
to  project  externally,  and  finally  the  head  also  appears.  In 
11 


82  BOARD   OP   AGRICULTURE. 

this  condition  the  creature  has  a  flask-shaped  form.  The  neck 
tapers  gradually  from  the  bladder  to  the  head,  and  is  divided 
transversely  into  a  series  of  many  short  joints.  The  head  is 
but  little  enlarged,  bearing  four  suckers,  as  usual,  and  in  the 


Figure  60. 


Figure  61. 


center  has  a  proboscis,  surrounded  by  two  rows  of  hooks,  con- 
taining from  sixteen  to  twenty-four  pairs.  Sometimes  there 
are  found  in  large  bladders  of  this  kind  a  few  secondary  blad- 
ders attached  to  the  inside  of  the  large  one,  produced  by  a 
process  of  budding,  somewhat  as  in  the  water-brain,  or  coenu- 
rus.  This  parasite,  as  thus  characterized,  was  formerly  sup- 
posed to  be  a  distinct  and  peculiar  species,  and  received  the 
name  of  "  Cysticercus  tenuicollis"  or  slender  necked  bladder- 
worm.  Recent  investigation  and  experiments  have,  however, 
proved  it  to  be  only  the  young  or  larval  condition  of  one  of  the 
common  tape-worms  of  the  dog  (Tcenia  marginata).  Blad- 
der-worms of  the  same  kind  are  found,  though  less  commonly,  in 
cattle  and  horses,  as  well  as  in  pigs,  monkeys,  and  many  other 
animals,  and  very  rarely  in  man.  Owing  to  the  large  size  to 


Figure  60.  Diving  bladder-worm,  from  a  sheep ;  natural  size.  Hearth  and 
Home,  after  Thudichum. 

Figure  61.  Head  of  Ttenia  marginata,  enlarged.  Hearth  and  Home,  after 
Thudichum. 


PARASITES  OF  ANIMALS.  83 

which  this  parasite  grows,  it  is  always  liable  to  produce  se- 
rious disease,  or  even  death;  but  the  symptoms  that  it  causes 
and  the  danger  will  depend  very  much  upon  the  situation  of  the 
tumors.  In  some  districts  it  is  extremely  common.  According 
to  Dr.  Thudichum,  it  occurs  in  nearly  every  sheep  slaughtered 
in  London  ;  and  the  dogs  that  feed  upon  the  offal  of  slaughter- 
houses nearly  always  have  the  mature  tape-worms  in  abun- 
dance. 

When  a  dog  swallows  one  of  these  bladders,  either  free  or 
in  its  cyst,  the  bladder  portion  is  digested,  and  the  head  be- 
comes protruded ;  on  reaching  the  intestine,  it  fastens  itself  to 
the  membrane  by  means  of  its  suckers  and  hooks.  In  this 
situation,  it  rapidly  develops  new  joints,  and  in  the  course  of 
three  or  four  months  becomes  a  mature  tape-worm,  about 
three  feet  in  length,  and  begins  to  discharge  its  ripe  joints 
filled  with  eggs.  A  dozen  or  more  of  these  tape-worms  may 
exist  together  in  the  intestine  of  one  dog.  In  general  appear- 
ance, this  tape-worm  (Tcenia  marginata)  resembles  the  pork 
tape-worm  of  man  (Tcenia  solium),  but  never  grows  so  large, 
and  its  neck  portion  is  much  thicker,  compared  with  the  size 
of  the  head  as  shown  in  Figure  61. 

The  first  hundred  joints  are  very  short ;  the  mature  joints  are 
squarish,  the  posterior  end  of  one  somewhat  overlapping  the 
anterior  end  of  the  next.  These  joints  contain  a  very  much 
branched  and  subdivided  female  organ,  with  an  oviduct  ter- 
minating on  one  edge  in  a  bell-shaped  orifice  ;  and  an  arbor- 
escently  branched  male  organ  or  spermary,  with  small,  round 
dilations  connected  with  the  small  branches.  Dogs  harbor- 
ing these  tape-worms  scatter  the  mature  joints  and  thousands 
of  eggs  everywhere  over  the  fields,  and  in  the  water  of 
streams  and  ponds.  The  sheep  and  cattle  swallow  the  eggs, 
either  with  their  food  or  water  or  both.  The  eggs  are  hatched 
in  the  stomach  of  the  sheep,  and  liberate  minute  worms, 
which  are  armed  with  three  pairs  of  hooks  for  boring  their 
way  through  the  tissues,  like  the  embryos  of  other  tape-worms. 
By  this  means,  these  embryos  force  their  way  through  the 
lining  membrane  of  the  intestine  into  the  blood-vessels,  and 
are  carried  to  various  parts  of  the  body.  Many  lodge  in  the 


84  BOARD   OF   AGRICULTURE. 

lungs,  heart,  and  other  organs,  and  cause  for  a  time  great  irri- 
tation and  inflammation  of  these  and  other  parts  by  their  move- 
ments in  forcing  and  boring  passages  for  themselves  in  the 
tissues  ;  but  they  all  eventually  perish,  while  still  small,  in 
such  localities,  and  those  that  get  into  the  liver  and  abdomi- 
nal viscera  are  the  only  ones  that  survive  and  develop  to  their 
full  size,  becoming  the  water-bladders,  or  "  Cysticercus  tenu- 
icollis"  first  described. 

The  complete  history  of  this,  like  the  other  tape-worms, 
previously  described,  has  been  ascertained  beyond  doubt  by 
direct  experiment.  In  this  case  the  water-bladders  have  been 
given  to  dogs,  and  at  the  proper  time  the  dogs  have  been  killed, 
when  the  mature  tape-worms  have  always  been  found  corres- 
ponding in  number  to  the  number  of  water-bladders  eaten, 
and  in  size  to  the  length  of  time.  And  then  the  eggs  or  joints 
of  the  tape-worms  have  been  given  to  lambs  ;  and  although 
such  lambs  generally  die  in  the  course  of  five  or  six  days, 
when  they  swallow  large  numbers,  yet  even  in  that  short  time 
the  young  worms  have  been  found  in  vast  numbers  already 
distributed  in  the  system ;  but  when  only  a  few  eggs  are  em- 
ployed, they  do  not  cause  immediate  death.  And  in  this  way 
Prof.  Leuckart  has  studied  their  complete  development.  This 
tape-worm,  in  its  mature  state,  does  not  inhabit  the  human 
body.  Dr.  Moller  even  swallowed  several  of  the  living  blad- 
der-worms without  any  result. 

When  these  young  worms  have  once  got  into  the  system  of 
a  sheep,  there  is  no  remedy.  In  this  case,  prevention  is  our 
only  hope  ;  and  to  this  end  the  same  means  should  be  used  as 
against  the  Tcenia  coenurus  and  T.  ec/iinococcus,  to  be  de- 
scribed farther  on.  Especial  care  should  always  be  taken  to 
destroy  the  water-bladders  and  all  other  parasites  observed  in 
slaughtering  animals,  as  well  as  those  removed  from  living 
animals  by  medicines  or  surgical  operations  ;  for  in  many  cases 
the  eggs  are  capable  of  retaining  their  vitality  for  many  weeks 
or  months.  They  should  never  be  thrown  aside  as  harmless, 
or  even  buried,  but  should  be  destroyed  by  scalding  hot  water 
or  fire.  Much  may  be  done,  also,  in  diminishing  the  numbers 
of  this  and  other  parasites  by  frequently  doctoring  those  dogs 


PARASITES  OF  ANIMALS. 


85 


that  are  worth  keeping,  or  are  necessary,  in  order  to  expel 
their  parasitic  worms,  of  which  there  are  generally  many 
kinds.  There  are  numerous  drugs  that  are  efficacious  for  this 
purpose,  some  of  which  are  mentioned  under  the  beef  tape- 
worm (page  191).  But  the  principal  difficiiltyis  this — those 
who  keep  the  most  dogs,  the  worst  dogs,  and  the  dogs  most 
likely  to  harbor  parasites  in  abundance,  are  the  very  persons 
who  are  least  likely  to  adopt  such  measures,  either  not  know- 
ing or  not  caring  for  the  consequences. 

Tcenia  coenurus  Kuch.,0/£/*e  Dog ;  audits  young,  the  "water- 

brain"  of  Sheep. 

In  the  substance  of  the  brain  of  sheep  there  is  often  found 
a  soft  tumor,  often  as  large  as  a  pigeon's  egg,  and  sometimes 
larger  than  a  hen's  egg,  which  is  filled  with  a  watery  fluid. 
Such  tumors  would  go  on  increasing  in  size  indefinitely,  until 

Figure  62. 


death  ensues.  But  even  long  before  the  result  becomes  fatal, 
the  health  is  seriously  impaired.  The  brain  is  often  found 
much  diseased,  and  in  part  quite  disorganized — a  state  of 
things  which  in  man  would  produce  incurable  insanity.  In 
sheep,  it  causes  "  staggers,"  "  gid,"  "vertigo,"  or  "  sturdy," 
and  other  cerebral  derangements.  This  disease  is,  in  most 

Figure  62. — Coenurus  or  water-brain  of   sheep.     Natural    size.     Hearth  and 
Home,  after  Thudichum. 


86 


BOARD   OF  AGRICULTURE. 


cases,  incurable,  and  such  diseased  sheep  are  too  often  sent 
to  the  market.  Fortunately,  man  cannot  be  infected  with 
this  parasite. 

When  one  of  these  tumors  is  removed  with  care,  it  will  be 
found  to  consist  of  a  thin,  white,  translucent  cyst  or  sac, 
roundish,  oval,  or  irregular  in  shape.  On  one  side  may  be 


Figure  63. 


Figure  64. 


seen  clusters  of  little  white  spots  (Figure  62).  If  the  spots 
be  examined  with  a  lens,  each  one  will  be  found  to  consist  of 
the  minute  head  and  neck  of  a  young  tape-worm,  projecting 
from  the  surface,  and  provided  with  four  suckers  and  a -circle  of 

Figure  65. 


hooks,  as  usual  in  young  tape-worms  in  this  stage  of  their 
growth  (Figure  63).  Or  else  the  heads  will  be  found  to  be 
withdrawn  into  the  sac,  each  in  its  own  capsule,  and  then 
the  spots  are  made  by  small  depressions  or  pits,  with  a  slit- 
like  opening  at  the  bottom.  If  the  interior  of  the  sac-mem- 
brane be  examined  with  a  microscope,  each  pit  will  be  found 

Figure  63. — Portion  of  the  outer  membrane,  with  the  heads  of  Ccenurus.  En- 
larged four  diameters.  From  Davaine. 

Figure  64. — Inner  surface  of  the  membrane  of  the  cyst,  with  inverted  heads, 
magnified.  Hearth  and  Home,  after  Thudichum. 

Figure  65. — Brain  of  shesp  in  which  the  young  embryos  of  C.cenurus  have  ex- 
cavated galleries.  Davaine,  after  Van  Benedeu. 


PARASITES   OF   ANIMALS.  87 

to  correspond  to  one  of  the  withdrawn  and   inverted  worms, 
as  represented  in  Figure  64. 

Each  little  worm  has  a  head  with  a  circle  of  hooks  in  the 
middle,  surrounded  by  four  suckers,  just  as  in  the  measle- 
worm  of  pork.  In  this  case,  each  little  worm  with  a  head  is 
the  larva  of  one  of  the  dog  tape-worms  (Tcenia  caenurus), 
hut  in  this  the  young  worms  have  the  power  of  propagating 
themselves  by  a  kind  of  budding,  in  a  manner  similar  to  that 
by  which  the  coral-animals  bud  from  each  other  and  so 
build  great  colonies.  Thus  it  is  that  one  of  these  little 
worms,  lodged  in  the  brain,  by  budding  produces  hundreds  of 
others  like  itself,  all  connected  together  by  the  membrane  of 
the  sac  ;  and  thus  the  tumor  constantly  grows  larger,  instead 
of  always  remaining  small,  as  does  the  measle-worm. 

Effects. 

Now,  if  a  dog  gnaws  a  skull  containing  such  a  tumor,  and 
swallows  the  whole  cyst,  or  any  part  of  the  membrane  that 
has  heads  on  it,  the  heads  will  be  liberated  from  the  mem- 
brane, and  each  one  will  fasten  to  the  lining  of  the  dog's 
intestine  by  means  of  its  suckers  and  hooks.  There  they  will 
rapidly  grow  larger  and  larger  ;  new  joints  will  be  formed  for 
the  body,  and  in  the  course  of  three  months  each  one  will  become 
a  small  tape-worm,  with  many  joints,  and  each  of  the  larger 
joints  will  have  both  male  and  female  organs,  and  will  be 
capable  of  propagating  the  race  by  itself.  The  female  organs 
of  each  joint  contain  thousands  of  eggs,  which  are  discharged 
when  mature,  and  passing  from  the  intestine  of  the  dog  in 
large  numbers,  they  will  be  scattered  about  freely  over  the 
pastures  and  fields  wherever  the  dogs  go.  If  a  lamb  or  sheep 
accidentally  swallows  some  of  the  eggs  with  grass  or  in  water, 
the  eggs  will  hatch  in  the  stomach  into  minute  worms.  These 
force  their  way,  by  means  of  their  six  little  hooks,  through 
the  lining  of  the  intestine  into  the  blood-vessels,  and  are  thus 
carried  to  different  parts  of  the  system ;  but  usually  only 
those  that  lodge  in  the  brain  live,  and  there  excavate  galleries 
(Figure  65)  and  grow,  and  bud,  thus  forming  the  "  water- 
brain,"  and  finally  kill  the  sheep.  Ccenurus  cysts  have  been 
observed,  however,  beneath  the  skin  of  sheep,  in  the  cellular 
tissue.  Similar  cysts  have,  also,  been  found  in  the  liver 


88  BOARD  OF  AGRICULTURE. 

of  rabbits,  and  in  squirrels,  and  other  animals,  so  that  dogs 
may  perhaps  obtain  the  same  tape-worms  by  eating  rabbits,  and 
then  give  the  "water-brain"  in  turn  to  lambs.  But  the. 
coenurus-like  cysts  of  rabbits,  etc.,  may  prove  to  be  a  distinct 
species,  which  does  not  produce  the  same  dog  tape-worm,  as 
several  writers  suppose.  Young  lambs  are  more  liable  to  be 
infected  by  this  parasite  than  sheep,  the  liability  decreasing 
with  age.  This  parasite  is  by  no  means  uncommon,  and  is 
always  abundant  in  proportion  to  the  number  of  dogs  in  any 
country.  Thus,  in  Iceland,  where  both  dogs  and  sheep  are 
kept  in  large  numbers,  Dr.  Krabbe  found  this  tape-worm  in 
eighteen  per  cent,  of  the  dogs,  while  the  two  other  tape-worms 
dangerous  to  sheep  were  found  even  in  much  greater  num- 
bers. "Giddy"  sheep  are,  of  course,  very  abundant  in  that 
unfortunate  country.  In  this  country  the  disease  is  far  more 
common  than  most  persons  suppose. 

That  this  disease  is  caused  in  the  manner  described  above, 
has  been  repeatedly  proved  by  direct  experiments  made  by  a 
number  of  naturalists.  The  following  by  Dr.  Kiichenmeister, 
was  one  of  the  earliest :  "  On  the  6th  of  January,  1854,  at  8 
o'clock  in  the  evening,  and  on  the  7th  of  January,  at  11  o'clock 
in  the  forenoon,  I  gave  some  mature  proglottides  (joints)  of  the 
Tcenia  coenurus  of  the  dog  to  six  lambs  of  from  six  to  nine 
months  old,  taken  from  three  different  flocks,  which  were  not 
subject  to  vertigo.  On  the  20th  of  January  the  animals  exhibit- 
ed the  first  symptoms  of  vertigo.  They  were  then  successive- 
ly killed,  and  presented  the  following  phenomena  on  exami- 
nation. 

On  the  seventeenth  day  after  the  introduction,  from  twenty 
to  thirty  vesicles  (Coenuri)  inhabited  the  surface  of  the  brain  ; 
the  substance  of  the  brain  was  hollowed  into  galleries  as  though 
a  Sarcoptes  had  been  formingits  passages  (see  Figure  65)  ;  the 
vesicles  were  still  free  and  without  envelopes,  and  of  the  size 
of  a  grain  of  millet. 

On  the  twenty-fifth  day  the  vesicles  were  larger.  On  the 
twenty-sixth  day  they  were  of  the  size  of  a  lentil ;  the  envel- 
opes began  to  be  formed,  and  the  first  traces  of  heads  appear- 
ed. On  the  thirtieth  day,  the  heads,  under  the  form  of  tuber- 


PARASITES   OF   ANIMALS.  89 

cles,  were  visible  to  the  naked  eye.  On  the  thirty-eighth  day, 
the  eminences  appeared  more  distinctly  on  the  surface,  and 
the  heads  exhibited  signs  of  their  suckers  and  hooks. 
Toward  the  forty-fifth  day  the  Coenuri  were  of  the  size  of  a 
bean,  and  the  cavities  in  which  the  heads  are  lodged  were 
formed."  Encysted  vesicles,  containing  strayed  and  aborted 
worms,  were  also  found  in  the  heart,  the  diaphragm,  and  the 
oesophagus.  Some  of  the  "  water-brains"  obtained  in  this  ex- 
periment were  given  to  a  dog  early  in  March,  and  in  due  time 
a  good  crop  of  the  mature  tape-worm  (Taznia  coenurus)  was 
obtained  by  killing  the  dog,  which  was  done  May  24th.  These 
were  immersed  in  white  of  eggs,  in  which  some  of  them  were 
kept  alive,  by  changing  it  daily,  for  eight  days,  and  sent  to 
several  other  naturalists  residing  in  other  parts  of  Europe,  at 
Louvain,  Copenhagen,  and  Giessen.  Prof.  Von  Beneden  re- 
ceived his  at  Louvain,  May  27th,  and  tried  the  following  ex- 
periments :  "  On  the  day  of  their  arrival,  at  9  o'clock  A.  M., 
half  a  proglottis  was  given  to  each  of  two  young  sheep,  about 
two  months  old,  and  in  the  afternoon  each  of  them  took  an 
entire  proglottis.  On  the  3d  of  June,  one  of  them,  marked 
No.  1,  swallowed  another  proglottis.  The  first  symptoms  of 
vertigo  made  their  appearance  on  the*13th  of  June  ;  on  the 
morning  of  the  15th,  I  was  told  that  the  one  marked  No.  2 
was  dying.  Its  head  was  burning  hot,  its  eyes  red,  its  legs 
bent  under  its  body  ;  it  beat  with  its  head  against  the  railings, 
and  turned  it  constantly  in  one  direction.  It  was  then  killed. 
The  upper  and  lower  surfaces  of  the  two  hemispheres  of  the 
brain  presented  irregular  grooves  which  might  be  taken  for 
the  deserted  tubes  of  certain  annelids  (Figure  65)  ;  these  have 
been  already  mentioned  by  M.  Kiichenmeister.  There  were 
about  a  dozen  of  them.  At  the  end  of  these  tubes  there  were 
the  same  number  of  Coenuri ,  almost  all  lodged  in  the  cortical 
substance  of  the  brain.  Some  of  them  were  removed  with  the 
membranes  of  the  brain.  They  were  of  nearly  the  same  size, 
about  three  or  four  millimetres  in  diameter.  These  Coenuri 
as  yet  only  consisted  of  a  simple  milk-white  vesicle  filled  with 
fluid.  The  heads  were  not  yet  to  be  seen.  *  * 

The  second  sheep  (No  1),  was  killed  on  the 
12 


90  BOARD   OF  AGRICULTURE. 

29th  of  June.  It  presented  nearly  the  same  symptoms  as  th  e 
former.  For  the  last  few  days  of  its  existence  the  right  fore- 
leg was  always  bent,  and  in  walking  it  could  not  support  it- 1 
self  upon  its  hoofs.  In  removing  the  brain  from  the  cranium, 
a  Ooenurus  of  the  size  of  a  small  nut  fell  upon  the  dissecting 
table.  Two  other  Ccenuri,  of  the  same  size,  were  found  in 
the  right  hemisphere,  one  above,  the  other  behind  ;  and  in 
separating  the  hemispheres  of  the  cerebellum,  I  found  two 
others  touching  the  quadrigeminal  tubercles.  The  left  lobe 
of  the  cerebellum  also  contained  one.  Eight  were  found  in 
all.  These  Ooenuri  were  nearly  all  of  the  same  size,  except 
two  or  three,  which  were  scarcely  larger  than  a  cherry-stone. 
Through  the  walls  of  the  larger  ones  the  naked  eye  could  dis- 
tinguish some  little  whitish  flakes,  the  indications  of  so  many 
heads  (scolices).  The  smaller  ones  had  no  appearance  of 
heads,  nor  of  the  place  where  they  were  to  rise.  The  Coenuri 
were  enclosed  in  a  membrane  of  recent  formation,  produced 
by  the  inflammation  of  the  neighboring  surfaces." 

Similar  experiments,  with  the  same  results,  were  tried  by 
Eschricht  at  Copenhagen,  and  Leuckart  at  Giessen,  to  whom 
tape-worms  from  the  same  dog  were  sent.  Three  sheep  were 
fed  by  Dr.  Esckricht.  Of  these  one  was  not  affected,  but  the 
other  two  became  ill  on  the  15th  and  16th  days  and  died  four 
days  afterward  with  the  symptoms  already  described,  and  in 
their  brains  the  same  kind  of  young  Coenuri  were  found. 

In  these  experimental  cases,  where  large  numbers  of  eggs 
are  given,  the  symptoms  come  on  violently  and  death  takes 
place  at  an  early  stage  in  the  development  of  the  worms,  but 
under  ordinary  circumstances  only  a  few  eggs  are  swallowed 
and  then  the  sheep  may  live  long  enough  to  allow  the  cysts  to 
become  much  larger,  with  more  numerous  heads.  The  num- 
ber of  the  heads  is  often  300  or  more  on  a  large  cyst,  and  each 
head  is  capable  of  forming  a  complete  tape-worm,  with  many 
joints.  Allowing  500  sexual  joints  to  each  tape-worm,  and 
each  joint  to  contain  5000  eggs,  there  might  result,  as  the  pro- 
geny of  one  egg  in  a  single  generation,  150,000  joints,  con- 
taining 750,000,000  eggs ! 

Remedies. — The  only  remedy  for  sheep  with  this  parasite  at 


PARASITES    OP  ANIMALS.  91 

work  in  the  brain,  would  be  trepanning,  and  that  can  seldom 
be  effectual,  unless  the  cysts  be  small  and  favorably  situated, 
which  is  not  often  the  case.  As  with  most  internal  parasites, 
instead  of  remedies,  we  must  seek  means  of  prevention.  It  is 
very  apparent  that,  in  this  case,  prevention  simply  demands 
the  absence  of  dogs  that  harbor  the  tape-worms,  from  all 
places  where  the  sheep  feed  or  drink.  Prevention  on  the 
part  of  dogs  can  be  secured  by  not  allowing  them  to  feed  on 
the  offal  of  slaughter-houses,  and  especially  the  heads  of  sheep. 
The  mature  tape-worms  can  be  expelled  from  dogs  by  the  or- 
dinary remedies  for  other  tape- worms,  some  of  which  are  men- 
tioned under  Tcenia  mediocanellata. 

Perhaps  the  most  effectual  of  these  remedies  is  oil  or  spir- 
its of  turpentine  mixed  with  castor  oil. 

Tcenia  echinococcus  Siebold,    of  the  Dog ;  and  its  young,  the 
hydatid  tumors  of  Man,  Sheep,  and  Cattle. 

This  is  by  far  the  most  important  and  dangerous  of  all  ces- 
tode  worms.  In  the  mature  state  it  lives  in  the  intestine  of 
dogs  and  wolves  in  great  numbers,  as  a  very  small  tape-worm, 
about  an  eighth  of  an  inch  long,  with  only  three  sexual  joints 
or  proglottides  (Figure  70).  In  its  larval  state  it  forms  com- 
pound cysts  and  tumors  in  a  great  variety  of  animals. 

Not  imfrequently  there  may  be  found  imbedded  in  the  sub- 
stance of  the  liver  and  lungs  of  sheep,  watery  tumors  of  con- 
siderable size,  sometimes  becoming  several  inches  in  diameter 
and  causing  serious  disease,  and  even  the  death  of  the  ani- 
mal. Similar  tumors  occur,  though  less  frequently,  in  the 
brain,  kidneys,  ovaries,  among  the  muscles,  and  in  various 
other  situations  in  sheep.  They  occur  also  in  pigs,  horses,  and 
cattle,  though  less  commonly  than  in  sheep,  but  unlike  the  Ccen- 
urus,  or  "  water-brain,"  these  tumors  are  not  confined  to  the 
lower  animals.  They  are  also  found  in  the  human  body,  and 
give  rise  to  incurable  and  most  horrible  diseases,  to  which  per- 
sons of  ail  classes  are  liable, 110  matter  how  wealthy  or  refined. 
That  large  numbers  of  human  beings  of  all  ages  and  condi- 
tions die  annually  from  diseases  caused  by  this  parasite  is  es- 
tablished beyond  a  doubt.  And  although  such  diseases  are 


92  BOARD   OP   AGRICULTURE. 

most  common  among  the  poorer  classes  of  society,  and  espec- 
ially among  those   who  associate   most  familiarly  with  dogs, 

Figure  66. 

Figure  67. 


they  are  by  no  means  confined  to  them.  Many  men  of  great 
eminence  and  talent  have  likewise  perished  from  the  same 
cause.  And,  unfortunately,  society  is  so  constituted  that  no 
one  can  be  certain  of  escaping  so  long  as  the  parasites  that 
produce  the  eggs  exist  in  the  dogs  of  every  country.  It  is 
estimated  that  500  persons  die  annually  by  this  parasite  in 
Great  Britain. 

These  tumors,  in  their  simplest  form,  or  when  young,  con- 
tain a  roundish  cyst  or  membranous  sac,  enclosing  a  watery 
fluid,  as  shown  in  Figure  66,  which  represents  of  natural  size 
a  parasite  of  this  kind  from  the  human  kidney.  More  fre- 
quently the  cysts  become  compound  by  a  process  of  budding, 
either  upon  the  outside  or  inside,  or  both  without  and  within 
the  membrane  of  the  original  cyst,  so  that  its  size  goes  on  in- 
creasing indefinitely,  sometimes  becoming  as  large  as  a  child's 
head,  and  often  completely  permeating  and  destroying  the 
liver,  lungs,  or  other  organs.  Thus  the  danger  becomes  con- 
stantly greater  and  greater  by  reason  of  the  pressure  upon 
and  destruction  of  the  adjacent  organs.  When  the  budding 
is  external,  it  results  in  a  cluster  of  secondary  cysts,  often  a 
dozen  or  more,  and  sometimes  hundreds,  all  more  or  less  con- 
nected together  (Figure  67).  And  each  of  the  external  second- 
ary or  daughter  cysts,  may  increase  and  multiply  itself  in  the 
same  way,  thus,  at  times,  producing  many  hundreds  of  other 
tertiary  cysts  or  "  grand-daughter  cysts."  By  internal  budding, 

Figure  66— rHydatid  or  echinococcus  cyst,  natural  size.  Hearth  and  Home, 
after  Thudichum. 

Figure  67. — Secondary  cysts  from  a  tumor  in  the  liver,  natural  size.  From 
Cobbold. 


PARASITES  OF  ANIMALS.  93 

secondary  or  daughter  cysts  are  formed  inside  the  primary 
ones,  and  then  others  inside  the  secondary  ones,  within  which 
the  heads  of  the  future  tape-worms  are  formed  by  a  peculiar 
budding  process.  If  the  inner  membrane  of  one  of  the  small 
cysts  be  examined  when  quite  fresh  with  a  good  microscope, 
there  will  be  seen  attached  to  it  by  means  of  slender  stalks, 
numbers  of  small  oval  or  rounded  heads,  looking  something 
like  fruit  on  a  miniature  plant,  as  shown  in  Figure  68,  which 
shows  a  few  of  these  heads  attached  to  the  inner  mem- 
brane of  a  cyst  from  an  echinococcus  tumor  of  a  sheep.  The 
heads  may  also  bud  forth  from  the  outer  as  well  as  the  inner 
surface  of  the  cysts,  or  brood-capsules,  as  they  are  called.  And 
these  heads,  either  external  or  internal,  may  become  changed 
by  an  enlargement  of  their  bladder-like  portion  into  new 
brood-capsules  or  cysts,  and  by  budding  produce  other  heads 
in  their  interior,  as  shown  in  Figure  69.  The  heads  are  found 
attached  to  the  inner  membrane  of  the  primary  cyst,  together 
with  secondary  cysts  or  brood-capsules ;  they  occur  in  the  same 
way  in  the  interior  of  the  secondary  cysts,  sometimes  associ- 
ated with  tertiary  cysts,  or  grand-daughter  vesicles;  and  also 
on  the  interior  of  the  tertiary  cysts.  They  sometimes  appear 
even  on  the  exterior  surface  of  the  secondary  and  tertiary 
vesicles.  In  all  these  situations  they  are  similar  in  appear- 
ance and  structure,  and  all  are  equally  capable  of  developing 
into  tape-worms  in  the  intestine  of  a  dog.  Many  of  the 
smaller  secondary  and  tertiary  brood-capsules  or  cysts  are  not 
more  than  T^  of  an  inch  in  diamter,  and  then  generally  coil- 
tain  only  three  or  four  heads. 

Each  of  the  oval  heads  is  a  hollow  sac,  which  contains  the 
real  head  of  the  young  tape-worm  turned  in  like  the  finger  of 
a  glove,  just  as  the  heads  are  turned  inward  in  the  ccenurus 
and  in  the  measles  of  pork,  or  the  young  of  any  other  tape- 
worm. Often  the  head  is  turned  outward,  as  is  seen  in  one 
case  in  Figure  68,  which  shows  well  the  four  suckers  around 
the  head  and  the  proboscis  in  the  middle  with  its  circle 
of  hooks.  These  same  organs  can  be  seen  indistinctly  even 
when  in  their  inverted  position,  as  in  the  other  he.ads  shown 
in  Figure  68,  owing  to  the  partial  transparency  of  the  mem- 


94  BOARD"  OP     AGRICULTURE. 

branes.  As  long  as  these  cysts  remain  in  a  living  animal, 
new  heads  are  constantly  formed,  by  their  peculiar  methods 
of  budding,  and  when  new  cysts  are  formed  either  within  or 
outside  of  the  older  ones,  they  develop  on  their  inner  mem- 
branes other  heads  in  the  same  way,  so  that  if  the  sheep  or 
other  animal  lives  long  enough  to  develop  a  large  tumor,  it  will 
finally  contain  many  thousands  of  these  minute  tape-worm 
heads.  In  examining  one  of  these  tumors  taken  from  a  dead 
animal,  most  of  the  heads  and  also  the  internal  secondary  cysts 
are  usually  found  floating  freely  in  the  watery  fluid  in  great 
numbers,  giving  it  a  turbid  appearance,  and  on  standing  they 
settle  to  the  bottom  as  a  granular  sediment.  This  is 
due  to  changes  after  the  death  of  the  parasite,  though  some 
of  the  secondary  cysts  may  be  free  during  life. 

Development. 

Now,  if  a  dog  eats  the  liver,  lungs,  kidney,  or  other  parts 
containing  such  tumors,  and  swallows  either  the  cysts  or  the 
detached  heads,  these  will  lose  the  enclosing  membrane,  stems, 
and  other  parts  that  are  no  longer  useful,  the  heads  with  their 
suckers  and  hooks  will  be  protruded,  and,  passing  into  the 
dog's  intestine,  each  one  will  fasten  itself  by  means  of  the 
hooks  and  suckers  to  the  soft  membrane  lining  the  intestine. 
In  this  situation  they  remain  and  soon  develop  a  small  body, 
having  only  three  separable  sexual  joints,  as  shown  in  Figure 
70,  which  represents  the  mature  tape- worm  {Tcenia  echinococ- 
cus)  greatly  magnified.  This  tape-worm  never  becomes  long, 
with  hundreds  of  joints,  as  do  the  pork  and  beef  tape-worms  of 
man.  It  is  only  about  an  eighth  of  an  inch  long  when  ma- 
ture. The  last  joint,  which  is  much  the  largest,  contains  both 
male  and  female  organs,  and  is  perhaps  capable  of  self-impreg- 
nation ;  it  is  therefore  a  complete  hermaphrodite.  After  this 
has  matured  and  discharged  its  eggs,  the  two  next  in  turn  de- 
velop their  sexual  organs  and  take  its  place.  In  Figure  70 
the  male  organ  may  be  seen  projecting  from  one  side,  and  the 
ovaries,  containing  many  eggs,  occupy  the  bulk  of  the 
joint.  The  eggs  pass  out  through  a  duct  that  opens  by 
the  side  of  the  male  organ,  and  each  egg  is  fertilized 
before  being  discharged.  Thousands  of  these  little  tape- 
worms, derived  from  one  large  cyst,  often  live  together  in 


PARASITES   OF   ANIMALS. 


95 


the  intestinefof  one  dog,  so  that  they  make  up  by  numbers 
what  they  lack  in  size.  Such  a  dog  is  constantly  discharging 
and  scattering  thousands  or  millions  of  the  extremely  mi- 
nute eggs  of  this  tape-worm  wherever  he  goeskJ^Tf^JBJR 

/%§**'      -^ 


Fiirare  68. 


JLibrary 


They  are  scattered  among  the  grass  in  fields  and  pas- 
tures ;  they  get  into  the  water  of  brooks  and  springs  ;  they 
are  liable  to  adhere  to  fruit  that  has  fallen,  or  to  lettuce 
and  other  garden  vegetables. 

Dr.  Cobbold  has  calculated  the  number  of  progeny  that 
might  proceed  from  one  egg  during  a  single  generative  cycle. 
Allowing  500  secondary  cysts  to  be  formed  and  10,000 
heads  or  scolices  to  be  developed  by  each  hydatid  cyst  of 
average  size,  these  might  produce  5,000,000  tape-worms, 
each  of  which  having  three  joints  that  become  free,  would 
give  15,000,000  joints  or  proglottides,  and  if  each  of  these 
contains  10,000  eggs,  the  whole  number  of  eggs  in  one  gen- 
eration, would  be  150,000,000,000! 


Figure  68. — Echinococcus  heads   attached  to  inside  of  brood-capsule,  greatly 
magnified.     Hearth  and  Home,  after  Thudichum. 
Figure  69. — A  head  or  scolex,  becoming  a  brood-capsule.    From  Leuckart. 


96  BOARD  OF   AGRICULTURE. 

Effects  and  Remedies. 

These  eggs  are  well  protected  by  a  shell,  but  when  taken 
into  the  human  stomach,  or  into  the  stomach  of  sheep,  cattle, 
or  pigs,  they  are  acted  upon  by  the  gastric-juice  and  then  im- 
mediately hatch,  The  embryo  is  a  very  minute  worm,  very 
different  from  the  parent,  and  provided  with  six  little  hooks, 
by  means  of  which  it  digs  its  way  through  the  lining  of  the 
intestine  into  the  blood-vessels,  and  entering  the  circulation 
they  are  carried  to  the  various  organs  of  the  body,  where  they 
develop  into  the  peculiar  cysts  first  described,  and  thus  cause 
disease  and  death.  When  lodged  in  the  brain,  they  are  most 
dangerous,  soon  causing  insanity  and  death  by  their  rapid 
growth  and  consequent  pressure.  In  the  lungs  they  are  also 
very  dangerous  and  often  fatal ;  in  the  liver  they  cause  severe 
disease,  often  terminating  fatally ;  and  in  other  organs  the 
effects  differ  according  to  the  nature  of  the  organ.  When 
the  lodgment  is  among  the  muscles,  or  near  the  exterior  of 
the  body,  the  tumors  may  be  removed  by  a  surgical  operation, 
or  even  by  simple  puncture,  they  maybe  destroyed.  The  dis- 
charge of  the  contents  is  fatal  to  the  life  of  the  hydatid 
opened,  but  there  may  be  many  others  adjacent  that  will  not 
be  affected.  Injections  of  iodine,  etc.,  after  opening,  are  un- 
necessary. When  in  the  internal  organs  there  is  generally 
no  remedy,  though  by  chance  the  cyst  may  of  itself  burst,  as 
sometimes  happens,  when,  if  the  discharge  takes  place  through 
some  natural  channel,  recovery  is  possible,  but  such  cases  are 
of  very  rare  occurrence.  In  the  majority  of  cases  the  true 
nature  of  the  disease  is  not  suspected  until  a  post  mortem 
examination  reveals  it,  or  until  the  tumors  burst  or  are 
opened,  when  a  microscopic  examination  of  the  matters  dis- 
charged gives  reliable  evidence ;  but  many  of  these  hydatid 
tumors  are  no  doubt  observed  and  treated  by  physicians,  who 
do  not  even  suspect  what  their  real  character  may  be,  because 
they  have  neither  suitable  instruments  nor  sufficient  knowl- 
edge to  make  the  requisite  examinations.  Chemical  tests 
may  be  applied  to  the  liquid  discharged,  it  is  said,  with  satis- 
factory results.  The  properties  of  the  fluid  are  described  as 
follows:  "If  the  sac  be  not  inflamed,  it  is  limpid,  has  a 
specific  gravity  of  1007  or  1009,  and  contains  no  albumen, 


PARASITES   OF   ANIMALS. 


97 


but  throws   down   a  copious  precipitate  with  a  solution  of 
nitrate  of  silver,  owing  to  its  strong  impregnation  with  com- 
mon salt.     These  characters  apply  to  no  other  fluid  in  the 
Figure  70.        body,    whether    healthy    or    morbid." — Dr. 
Murchison.     In  some   cases  hydatid  tumors 
situated  in  the  liver  and  other  internal  organs 
have  been  opened  from  the  exterior,  with  suc- 
cess, by  skillful  surgeons,  but  these  operations 
are  always  dangerous  and  often  immediately 
fatal.     The   escape   of    the    fluid,  with   the 
minute  cysts  and  heads  contained  in  it,  into 
the  abdominal  cavity,  will  give  rise  to  other 
tumors,  and  thus  increase  the  disease,  even  if 
death  does  not  immediately  result. 

This  is. eminently  a  case  where  "  an  ounce 
of  prevention  is  worth  a  pound  of  cure."  The 
means  of  prevention  are  simple,  though  not 
easy  of  application  in  all  cases.  The  iirst  and 
most  important  rule  is  to  diminish  the  num- 
ber of  dogs  to  the  utmost  possible  extent,  and 
then  to  keep  them  at  the  minimum  number ; 
second,  avoid  as  much  as  possible  the  prox- 
imity of  dogs  and  sheep  ;  third,  avoid  feeding 
dogs  with  uncooked  livers  or  other  offal  of 
sheep  containing  these  parasites,  or  never  give 
them  such  raw  food  without  careful  exami- 
nation ;  fourth,  avoid  too  much  familiarity 
with  dogs,  and  especially  between  children 
and  dogs ;  fifth,,  be  careful  not  to  eat  lettuce, 
fallen  fruit,  or  other  raw  food  that  has  not 
been  thoroughly  washed,  both  on  account  of 
this  and  other  parasites  j  sixth,  avoid  by  all 
means  possible  the  use  of  impure  water,  or  water  liable  to 
be  contaminated  by  eggs  of  parasites  and  excreta  of  animals, 
both  for  household  purposes  and  to  supply  sheep,  cattle,  and 
horses,  for  such  water  is  not  only  liable  to  contain  echino- 

Figure  70. — Mature  Tcenia  echinococcus,  much  enlarged.     Hearth  and  Home, 
after  Leuckart. 

13 


98  BOARD   OF   AGRICULTURE. 

coccus  eggs,  but  those  of  several  other  tape-worms,  round- 
worms,  and  many  other  parasites,  and  is  of  itself  unhealthy 
and  often  the  prolific  cause  of  disease.  If  water  from  a  good 
well,  or  a  well  protected  spring,  cannot  be  had,  the  water 
should  be  carefully  filtered,  and  by  preference  through  char- 
coal. Most  of  the  water  consumed  in  our  cities,  both  from 
wells  and  the  water-works,  is  wholly  unfit  to  drink  without 
filtering.  In  cities  with  loose  sandy  soils  the  well-water  is 
the  worst  possible. 

Finally,  dog-kennels  and  other  places  much  frequented  by 
dogs,  should  be  frequently  cleaned  and  the  litter  burned, 
while  frequent  sprinklings  with  strong  petroleum  water  or  a 
solution  of  carbolic  acid  in  water  should  be  used  to  destroy 
the  eggs  that  may  have  escaped  from  the  intestine.  By  these 
precautions  the  numbers  of  this  and  several  other  dog-parasites 
might  be  much  diminished.  Dogs  might  also  receive  a 
thorough  course  of  medical  treatment,  once  in  three  months 
to  expel  all  their  intestinal  worms,  with  great  advantage,  and 
this  might,  with  propriety,  be  made  obligatory  by  law.  In 
this  case  the  dogs  should  be  confined  while  treated  and  all 
excreta  should  be  burned. 

The  frequency  of  this  parasite  is  in  direct  proportion  to  the 
extent  to  which  the  precautions  are  neglected  in  different 
countries.  In  Iceland,  the  conditions  for  its  rapid  increase 
and  perpetuation  have  been  favorable,  and  in  that  unfortunate 
country,  Dr.  Krabbe  states  that  there  are  at  all  times  about 
eighteen  hundred  patients  suffering  with  severe  forms  of  this 
parasitic  disease — a  number  equal  to  about  one-fortieth  of  all 
the  inhabitants.  In  some  districts,  the  proportion  is  said  to 
be  one  in  every  seven,  and  scarcely  a  family  can  be  found 
without  two  or  more  cases  !  It  is  also  stated  that  one-sixth 
of  all  the  deaths  are  due  to  diseases  caused  by  this  parasite ! 
The  number  both  of  dogs  and  sheep  in  Iceland  is  very  large, 
and  the  dogs  mingle  with  the  natives  and  live  with  them  in 
their  rude  dwellings,  and  are  used  in  bringing  the  sheep  to- 
gether, so  that  abundant  opportunities  occur  for  propagating 
the  parasite.  According  to  Dr.  Krabbe,  there  is  one  dog  for 
every  three  to  five  inhabitants  in  Iceland,  while  in  Great 


PARASITES   OF   ANIMALS.  99 

Britain,  with  a  high  tax  on  dogs,  there  is  only  one  to  fifty. 
Doctor  Krabbe  found  the  echinococcus  tape-worms  in  twenty- 
eight  out  of  one  hundred  Icelandic  dogs  examined,  while  in 
Denmark  he  found  them  in  less  than  one  per  cent,  of  the 
three  hundred  and  seventeen  dogs  examined  for  this  purpose. 

Tape-worm  of  the  Horse  (  Tcenia  perfoliata   Goeze). 

This  is  a  small  species,  seldom  becoming  more  than  three 
inches  long  and  a  third  of  an  inch  broad.  The  head  is  rather 
square,  with  four  prominent  suckers,  but  without  a  proboscis 
and  hooks.  There  is  no  distinct  neck,  the  first  joints  behind 

Figure  71.  Figure  72. 


the  head  being  broad,  but  short.  There  are  about  45  joints 
in  full-grown  specimens.  The  reproductive  organs  open  on 
one  edge  of  the  joints,  the  first  22  segments  having  both  male 
and  female  organs,  the  rest  only  female. 

It  occurs  quite  frequently,  in  considerable  numbers,  in  the 
coecum  and  colon  of  the  horse,  and  more  rarely  in  the  small 
intestine.  The  development  and  the  source  from  which 
horses  derive  them  are  unknown.  The  larvae  may,  perhaps, 
live  in  insects  accidentally  swallowed  with  grass.  It  does  not 
appear  to  produce  any  serious  disease,  unless  in  great  num- 
bers, and  may  be  expelled  by  the  same  medicines  used  against 
the  human  tape-worms. 

A  still  smaller  species,  T.  mamillana  Mehlis,  only  about 
half  an  inch  long,  and  also  without  a  distinct  neck,  but  with 
wedge-shaped  joints,  lives  in  the  large  intestine  of  the  horse. 
A  much  larger  species  than  either  of  these  (T.  plicata  Rud.) 
lives  in  the  small  intestine  and  sometimes  in  the  stomach  of 
the  horse.  It  grows  to  the  length  of  three  feet  or  more,  and 
has  a  remarkably  large  head,  with  four  suckers,  but  no  hooks 

Figure  71. — Young  Tcenia  perfoliata,  natural  size.    From  Cuvier. 
Figure  72. — Head  of  T .  perfoliata,  magnified.    From  Cuvier. 


100  BOARD  OF   AGRICULTURE. 

or  proboscis.  The  neck  is  short  and  thick,  transversely 
plicated,  and  the  reproductive  organs  are  in  a  single  series  on 
one  edge.  If  in  considerable  numbers,  this  species  may  pro- 
duce serious  symptoms,  such  as  loss  of  flesh,  tight  skin,  loss 
of  strength  and  spirit,  and  general  debility. 

The  Sheep  Tape-worm  (  Tcenia  expansa  Rudolphi) . 

This  species,  which  is  found  both  in  sheep  and  cattle,  grows 
to  the  length  of  eight  or  ten  feet,  varying  in  breadth  from  a 
quarter  of  an  inch  to  upward  of  an  inch,  in  large  specimens. 
The  head  is  very  small  with  four  suckers  directed  forward, 
and  close  together.  The  neck  is  scarcely  distinct,  or  very 
short.  The  posterior  border  of  the  joints  are  uneven,  divided 
up  into  rounded  lobes  and  notches,  or  wavy.  The  reproduc- 
tive organs  are  double,  opening  on  each  edge  of  every  joint. 
Its  young  stage  is  unknown,  and  consequently  the  source 
from  which  the  sheep  obtain  it.  It  does  not  appear  to  be  very 
common  in  this  country,  judging  from  the  few  cases  recorded. 
In  Germany  it  is  very  common  in  sheep.  It  does,  without 
doubt,  produce  effects  in  sheep  similar  to  those  caused  by  the 
tape-worms  in  man. 

Tcenia  cucwnerina  Bloch,  of  the  Dog. 

This  species  is  very  common  in  the  small  intestine  of  the 
dog.  It  grows  to  the  length  of  ten  or  fifteen  inches  up  to 
nearly  ten  feet,  with  a  width  of  one-twelfth  to  one-eighth  of 
an  inch.  The  head  is  somewhat  rhomboidal,  with  four  sucke  rs 
and  a  central  proboscis,  which  is  surrounded  by  three  circles 
of  claw-shaped  hooks,  the  whole  number  being  about  48. 
The  mature  joints  are  elliptical,  or  shaped  somewhat  like  the 
seed  of  a  melon  or  cuciimber.  From  this  peculiarity  it  takes 
its  name.  There  are  two  genital  orifices  to  each  joint,  one 
in  the  middle  of  each  edge.  The  eggs  are  much  fewer  in 
each  joint  than  in  most  other  tape-worms.  Its  development 
is  unknown.  It  has  been  supposed  that  the  larvae  live  in  flies 
or  other  insects. 

When  in  large  numbers  in  a  dog,  it  occasions  more  or  less 
severe  symptoms,  especially  if  associated,  as  it  usually  is, 
with  several  other  species  of  tape-worms  and  round-worms. 
It  can  be  expelled  by  the  same  remedies  mentioned  under 
some  of  the  previous  species. 


PARASITES   OF   ANIMALS.  101 

Tcenia  elliptica  Batsch  is  a  similar  species  living  in  the  cat, 
and  by  some  is  thought  to  be  the  same. 

Several  tape-worms  of  the  dog  have  already  been  de 
scribed  (Tasnia  echinococcus,  T.  coenurus,  T.  marginata), 
but  there  is  another  that  is  equally  common  in  some  districts. 

Tcenia  serrata  Goeze  closely  resembles  T.  ccenurus  and  T. 
marginata.  The  larva?  live  among  tho  viscera  of  rabbits  and 
hares,  producing  small  round  cysts,  and  the  dogs  get  this  tape- 
worm by  eating  rabbits  or  the  refuse  thrown  aside  in  dressing 
them.  The  young  state  or  larva  was  formerly  named  Cysti- 
cercus  pisiformis,  in  allusion  to  the  pea-shaped  cysts. 

The  Broad  Tape-worm  of   Man  (Bothriocephalus  latus 
Bremser) . 

The  genus  Bothriocephalus  differs  greatly  from  the  true 
tape- worms  (Tcenia)  in  many  anatomical  characters,  but  has 
a  similar  form  of  body,  divided  into  many  flat  joints.  The 
head  has  no  suckers,  but  is  long-oval  in  shape,  with  a  long 
and  deep,  groove  on  each  side.  It  has  no  proboscis  and  no 
hooks.  The  reproductive  organs  open  at  the  middle  of  the 
side  of  each  joint,  instead  of  the  edge. 

There  are  numerous  species  living  in  fishes  and  quite  a 
number  in  birds.  The  present  species  grows  to  an  enormous 
size — probably  larger  than  any  other  known  tape-worm.  It 
grows  to  the  length  of  25  or  30  feet,  and  according  to  some 
authors  to  50  or  60  feet.  It  is  sometimes  an  inch  wide.  The 
joints  seldom  break  off,  either  singly  or  in  chains,  but  the 
eggs  are  discharged  by  the  bursting  of  the  joints  while  still 
attached  within  the  body  of  the  infested  person.  The  male 
and  female  organs  oprn  separately,  the  male  organ  being  a 
little  in  advance  of  the  female  orifice.  The  female  uterine 
organ  forms  a  sort  of  rosette,  with  eight  or  ten  lobes,  around 
the  external  orifice. 

Its  fertility  is  remarkable,  even  for  a  tape-worm.  Prof. 
Eschricht  found  in  one  specimen  10,000  joints  ;  allowing  each 
of  these  to  contain  only  a  thousand  eggs,  this  worm  would 
have  produced  10,000,000  young.  The  full  history  of  this 
parasite  is  not  yet  known.  The  eggs,  however,  will  hatch  in 
water,  producing  curious  embryos,  which  are  provided  with 
vibrating  cilia  by  means  of  which  they  swim  around  for  a 


102 


BOARD   OF   AGRICULTURE. 


few  days.  The  external  skin,  with  the  cilia,  is  then  cast  off, 
liberating  a  very  different  looking  embryo  or  larva,  which  is 
provided  with  six  boring  hooks,  similar  to  those  of  the  em- 
bryos of  ordinary  tape-worms.  Their  subsequent  history  has 
not  been  ascertained,  but  it  is  probable  that  they  enter  some 
fish  (most  likely  trout  and  salmon)  and  become  encysted 
among  the  muscles,  and  that  persons  who  eat  imperfectly 
cooked  or  raw  dried  fish  get  the  parasite  in  that  way. 

It  is  remarkable  that  this  species  is  not  known  to  be  indig- 
enous in  any  but  European  countries,  and  even  in  Europe  it 
is  peculiar  to  certain  districts.  It  is  particularly  common  in 
certain  parts  of  Switzerland.  In  Geneva  it  is  said  that  about 
one-fourth  of  all  the  inhabitants  are  afflicted  with  this  worm. 
It  occurs  also  in  some  parts  of  Russia,  Poland,  and  Prussia. 
In  America  it  has  only  been  observed  in  emigrants  from 
Europe,  and  in  persons  who  have  traveled  in  the  European 
countries  where  it  naturally  occurs.  It  causes  similar  symp- 
toms and  is  removed  by  the  same  remedies  as  the  common 
tape -worms. 

TREMATODE   WORMS. 

The  Liver-fluke  of  Sheep  and  Cattle  (Fasciolahepatica  Linn.). 
This  common  and  notorious  parasite  has  a  very  flat  body, 
different  on  the  two  sides,  and  more  or  less  oval  in  form,  the 
anterior  end  suddenly  narrowing  to  a  sort  of  neck,  which 
tapers  off  to  the  mouth  end,  where  it  is  either  rounded  or 
pointed.  The  posterior  end  of  the  body  is  Figure  78. 
somewhat  tapering,  but  blunt.  Ordinary  speci- 
mens are  about  three-quarters  of  an  inch  long 
and  half  an  inch  wide,  but  large  ones  become 
an  inch  and  a  quarter  long  and  three-quarters 
broad.  While  living  they  often  curl  up  the  ends 
of  the  body,  toward  the  lower  side.  The  color 
is  pale  brownish  or  greenish  yellow,  sometimes 
with  a  faint  rosy  tint.  At  the  anterior  end  of 
the  body  there  is  a  small,  cup-shaped  sucker,  at 
the  bottom  of  which  the  mouth  is  situated 
(Figure  73,  a)  ;  near  the  origin  of  the  neck- 
like  portion,  on  the  middle  line  of  the  lower  side,  there  is 


PARASITES   OF   ANIMALS.  103 

another  larger  sucker  (6),  with  no  opening  at  its  bottom ; 
just  in  advance  of  this  there  are  situated,  side  by  side,  the 
male  and  female  genital  orifices  (c).  The  external  male 
organ  is  long,  slender,  and  when  protruded  is  curved  in  a 
spiral.  It  can  be  retracted  into  a  small  cavity. 

Anatomy. 

The  reproductive  system  is  very  largely  developed  and  com- 
plicated. The  male  organs,  or  testicles,  consist  of  large 
clusters  of  vermiform,  convoluted,  yellowish  tubes,  situated 
in  the  middle  region  of  the  body,  and  filling  up  about  one- 
half  of  the  whole  interior.  The  female  organs,  for  they  are 
hermaphrodites,  are  also  largely  developed  and  complicated. 
The  lateral  and  hinder  parts  of  the  body  are  filled  with  in- 
numerable, very  small,  yolk-sacks,  which  communicate,  by  a 
complicated  system  of  branched  ducts,  with  a  heart-shaped 
ovary,  and  this  in  turn  has  a  short  duct  leading  to  the  uterus- 
like  organ,  which  consists  of  a  convoluted,  wide  tube,  forming 
a  sort  of  rosette  behind  and  around  the  ventral  sucker.  The 
uterine  tubes  show  through  the  skin  and  are  brownish  yellow, 
owing  to  the  numerous  minute  eggs  with  which  they  are  filled. 
These  eggs  are  discharged,  one  by  one,  from  the  small  ex- 
ternal orifice  as  fast  as  they  become  mature.  The  mouth 
communicates  with  a  small  dilated  oesophagus,  and  this  gives 
rise  to  two  large  intestinal  tubes,  which  diverge  in  advance  of 
the  genital  orifice  and  extend  backward,  along  each  side,  to 
near  the  posterior  end,  sending  off  numerous  lateral  branches, 
which  again  subdivide  into  many  short  divergent  branchlets, 
as  shown  in  Figure  73,  d.  The  branches  of  these  digestive 
tubes  are  all  closed  at  the  ends,  and  they  communicate  with 
the  exterior  only  through  the  mouth.  In  life  these  tubes  are 
all  filled  with  food,  consisting  chiefly  of  bile,  with  some  blood- 
corpuscles,  etc.  Another  system  of  numerous,  arborescently 
branched  tubes  is  found  nearer  the  dorsal  surface,  and  as  they 
show  through  the  skin,  on  that  side,  they  may  be  examined 

Figure  73. — Fasciola  hepatica,  natural  size,  seen  from  below ;  a,  mouth  and 
oral  sucker ;  b,  ventral  sucker ;  c,  genital  orifice ;  d,  branches  of  intestine.  From 
Cuvier. 


104  BOARD  OF  AGRICULTURE. 

with  an  ordinary  lens.  These  tubes  commence  in  fine,  rootlet- 
like  branches,  with  rounded  and  closed  ends,  but  the  small 
branches  constantly  unite  into  larger  trunks,  which  in  turn 
all  unite  into  one  main  trunk,  running  along  the  middle  line 
of  the  body,  and  this  terminates  in  an  external  orifice  at  the 
posterior  end.  The  use  of  this  system  of  tubes  is  to  remove 
the  waste  materials  from  the  body.  It  may  therefore  take 
the  place  both  of  the  kidneys  and  liver  of  the  higher  animals. 
There  is  110  blood  circulation  and  no  true  blood  in  these 
animals. 

Development. 

The  fluke  is  a  very  prolific  creature.  Prof.  Leuckart  esti- 
mates that  the  ovaries  may  at  any  one  time  contain  45,000 
eggs.  The  number  of  broods  that  they  produce  is  not  known. 
The  eggs  that  are  discharged  pass  out  of  the  intestine  of  the 
sheep,  or  other  animal  in  which  they  live,  with  the  excre- 
ment. Those  that  get  into  water  or  moist  places  hatch  after 
several  weeks,  producing  minute  conical  embryos,  which  are 
covered  with  vibrating  cilia  or  lashes,  by  means  of  which 
they  swim  freely  about  in  the  water.  In  this  state  the  em- 
bryo is  YJJTJ-  of  an  inch  long  and  -§$•$  of  an  inch  broad  at  the 
larger  end.  The  cilia  are  T^  of  an  inch  long. 

In  a  few  days  the  external  skin,  with  the  cilia,  is  cast  off, 
and  after  that  the  embryos  are  obliged  to  creep  about,  instead 
of  swimming.  Its  farther  development  has  not  been  traced, 
but  it  probably  has  a  history  similar  to  that  of  other  species 
of  flukes  of  which  the  entire  history  is  known.  Therefore  it 
is  supposed  that  the  young  embryos,  above  described,  attach 
themselves  to  the  bodies  or  enter  the  tissues  of  the  fresh- 
water spiral  snails,  such  as  Limncea  and  Physa.  In  this 
situation  the  form  probably  changes,  and  they  become  the  so- 
called  "  nurses,"  and  then  a  brood  of  larvae  of  another  form 
is  developed  in  their  interior,  by  a  process  of  internal  budding. 
These  larvae  are  provided  with  a  tail  and  have  a  form  some- 
what resembling  minute  tad-poles.  In  this  state  they  are 
known  as  cercarice.  They  are  finally  discharged  from  the 
body  of  the  "  nurses,"  and  escaping  from  the  snails,  may 
again  swim  actively  about  in  the  water,  by  means  of 


PARASITES   OP   ANIMALS.  105 

their  tails,  but  eventually  they,  in  all  probability,  again  enter 
the  bodies  of  other  small  snails,  and  losing  their  tails,  become 
encysted  ih  Mttle  capsules.  Finally  these  snails,  with  their 
parasites,  are  swallowed  by  sheep  and  cattle,  while  adhering 
to  the  herbage  growing  on  moist  land  or  near  the  water, 
or  when  adhering  to  water-cresses  they  might  be  swallowed 
by  mankind.  In  the  stomach  and  intestine  of  these  higher 
animals  they  are  again  liberated  from  their  cysts.  They  then 
gain  access  to  the  liver,  where  they  rapidly  develop  their 
sexual  organs  and  become  mature.  Eventually,  after  they 
have  matured  and  perhaps  discharged  a  large  part  of  their 
eggs,  they  themselves,  or  at  least  a  part  of  them,  enter  the 
intestine  and  are  discharged,  while  still  living,  in  company 
with  innumerable  eggs.  The  eggs  that  they  still  contain  may 
be  laid  after  they  reach  the  earth  or  water.  These  eggs  are 
exceedingly  minute  and  may  be  diffused  in  various  ways,  as 
by  rains,  winds,  insects,  and  the  feet  of  animals,  and  getting 
into  water,  or  moist  situations,  they  are  ready  to  hatch  and 
commence  another  series  of  transformations. 

The  history  of  most  of  the  flukes,  which  have  hitherto  been 
fully  investigated,  agrees  in  the  main  with  that  above  given, 
and  there  can  be  little  doubt  but  that  this  will  prove  to  be  the 
case  with  the  common  fluke,  when  its  full  history  shall  have 
been  ascertained.  At  any  rate  it  is  certain  that  the  eggs  can 
hatch  only  in  water,  or  in  moist  places.  Therefore  it  is  evi- 
dent that  sheep  and  cattle  will  be  much  more  liable  to  the 
disease  when  kept  in  low  wet  pastures,  than  in  dryer  and 
more  elevated  situations  ;  and  also  that  wet  seasons  will  be 
favorable  for  the  parasites  and  dry  ones  unfavorable.  These 
conclusions  have  been  fully  sustained  by  the  experience  of 
sheep-owners  in  all  countries. 

Modes  of  Occurrence. 

The  liver-fluke  is  one  of  the  few  internal  parasites  that  is 
capable  of  living  in  several  very  different  animals.  It  is  most 
common  in  sheep  ;  less  so  in  cattle,  goats,  horses,  and  the 
ass ;  and  quite  rare  in  man.  It  has  also  been  found  in  the 
hog,  elephant,  camel,  beaver,  squirrels,  rabbit,  hare,  deer, 
and  antelopes  of  several  kinds,  and  in  the  great  kangaroo. 
14 


106  BOARD   OF   AGRICULTURE. 

It  is  chiefly  found  in  the  gall-bladder  and  bile  ducts,  but 
occurs  also  in  the  intestine,  and  sometimes  in  blood  vessels. 
In  the  human  subject  it  has,  in  some  instances,  been  found  in 
tumors  beneath  the  skin.  In  these  cases  it  is  supposed  that 
the  larvae  entered  from  the  exterior  by  boring  through  the 
skin. 

Effects. 

The  injurious  effect  of  this  parasite  is  best  known  in  the 
case  of  sheep.  In  these  animals  it  produces  the  fatal  disease 
generally  known  as  "  rot,"*  "  water-rot,"  or  "  fluke-rot."  In 
severe  cases  of  this  disease  there  are  always  large  numbers  of 
flukes  in  the  bile-ducts- and  gall-bladder, — often  several  dozens 
and  sometimes  several  hundreds,  or  even  a  thousand  in  some 
fatal  cases.  A  few  may  exist  in  a  sheep  without  causing  any 
marked  disease  ;  in  proportion  to  the  number,  the  symptoms 
become  more  marked  and  the  disease  more  fatal.  In  some 
wet  seasons,  and  in  certain  districts,  these  parasites  have 
destroyed  immense  numbers  of  sheep.  Thus  in  1830-1  it  is 
estimated  that  between  one  and  two  million  sheep  died  of 
this  disease  in  Great  Britain.  If  the  number  was  but  1,500,- 
000,  it  would  represent  a  loss  equal  to  about  $20,000,000.  In 
a  single  year,  in  England,  individual  farmers  have  lost  from 
300  to  800  sheep  in  the  same  way.  In  France,  during  the 
year  1812,  according  to  Davaine,  300,000  sheep  died  by  the 
same  cause  in  the  vicinity  of  Aries,  and  90,000  at  Nimes 
and  Montpellier.  In  Germany,  Holland,  and  most  other 
European  countries  similar  disastrous  outbreaks  of  the  dis- 
ease have  occurred  every  few  years,  while  during  the  most 
favorable  years  the  aggregate  annual  loss  is  far  greater  than 
is  generally  supposed.  In  this  country  there  are  no  reliable 
statistics  by  which  the  losses  from  this  cause  can  be  estimated. 
Yet  there  can  be  no  doubt  but  that  it  amounts  in  reality  to  a 
large  sum  annually.  Even  those  sLeep  that  have  the  disease 
in  a  milder  form  and  are  sent  to  the  market  before  they  be- 
come too  sick  to  be  moved,  lose  very  much  in  value,  and  are 


*This  must  not  be  confounded  with  an  entirely  different  disease,  known  as 
"  foot-rot." 


PARASITES   OF  ANIMALS.  107 

really  unfit  for -food,  though  it  is  to  be  feared  that  farmers,  as 
well  as  butchers,  are  not  always  over  scrupulous  in  such  cases. 

Symptoms. 

In  severe  cases  any  one  at  all  familiar  with  sheep  can 
readily  detect  the  disease  even  by  the  general  looks  of  the 
animal.  They  also  show  a  peculiar  weakness  in  the  loins 
when  the  hand  is  pressed  along  the  back  over  that  region. 
In  very  bad  cases  the  back  becomes  hollow  and  the  belly 
hangs  down,  while  the  sheep  become  more  and  more 
emaciated  and  weak,  dull,  and  dejected,  with  a  feeble  gait. 
The  skin  loses  its  natural  color  and  becomes  dry,  while  the 
wool  is  also  harsh  and  dry,  and  conies  off  easily. 

The  skin  on  the  inner  parts  of  the  thigh,  especially  where  it 
is  naked,  becomes  dry  or  scaly  early  in  the  progress  of  the  dis- 
ease. The  eye  affords  very  certain  evidence,  even  at  an  early 
stage,  so  that  even  shepherd  boys  are  able  to  select  from  a 
flock  those  that  are  diseased,  by  this  symptom  alone.  If  the 
lids  be  turned  back  and  the  membrane  at  the  corner  of  the  eye 
be  pushed  away,  the  conjunctiva  and  other  parts  will  present 
an  unnatural  watery  appearance,  the  vessels  being  swollen 
and  filled  with  pale  or  yellowish  colored  blood,  When  the 
disease  is  farther  advanced  the  blood-vessels  lose  their  color 
and  are  scarcely  distinguishable,  though  a  few  of  them  may 
be  swollen  and  filled  with  dark,  unhealthy  looking  blood. 

Remedies. 

It  can  be  safely  stated  that  when  these  parasites  have  once 
entered  the  liver  in  considerable  numbers  there  is  no  known 
specific  remedy.  All  that  can  be  done  is  to  keep  up  the 
general  health  and  strength  of  the  animal  until  nature  effects 
a  cure,  or  until  the  parasites  complete  the  natural  course  of 
their  lives  and  voluntarily  leave  the  sheep.  To  this  end  the 
afflicted  animals  should  be  removed  to  a  dry  pasture  or  good 
shelter,  and  be  liberally  fed  with  a  variety  of  nutritious  and 
palatable  food,  while  they  should  be  freely  supplied  with  salt. 

This  is  another  of  those  instances  where  prevention  is  far 
easier  and  better  than  cure.  From  what  we  already  know  of 
the  history  of  the  parasite  it  is  evident  that  sheep  will  be 


108  BOARD   OF  AGRICULTURE. 

little  liable  to  get  it  if  pastured  on  uplands,  or  other  dry 
places,  and  supplied  with  pure  spring  water,  by  preference 
from  a  trough  or  other  similar  arrangement.  On  the  other 
hand,  sheep  pastured  on  meadows,  or  swampy  lands,  or  in 
places  where  they  have  access  to  the  marshy  banks  of  streams, 
ponds,  and  swamps,  will  be  far  more  liable  to  get  this  and 
several  other  parasites. 

An  exception  should,  however,  be  made  in  the  case  of  salt 
marshes  and  meadows,  for  sheep  pastured  in  such  places  sel- 
dom get  the  disease.  This  is  probably  owing  to  the  fact  that 
the  fresh  water  snails,  that  harbor  the  young  flukes,  cannot 
live  in  salt  or  brackish  water. 

Smaller  Liver-fluke  (Distoma  lanceolatum  Mehlis). 

This  species  is  also  found  in  the  bile-duct  and  gall-bladder 
of  sheep  and  cattle,  and  occasionally  in  man.  It  is  sometimes 
associated  with  the  common  fluke.  It  is  much  smaller,  the 
length  being  about  one-third  of  an  inch  and  the  breadth  an 
eighth.  It  has  a  smooth,  flat,  lance-shaped  body,  broadest 
behind  the  middle,  narrowing  to  each  end,  the  mouth-end 
being  most  pointed.  There  are  two  suckers,  as  in  the  com- 
mon fluke,  the  one  at  the  front  end  having  the  mouth  at  the 
bottom. 

The  anatomy  is  quite  different,  for  in  this,  as  in  all  other 
true  Distomas,  the  digestive  tube  only  forks  once,  each  branch 
remaining  a  simple,  closed  tube,  running  down  on  each  side 
of  the  middle  region  of  the  body.  The  testicles  are  two 
large,  roundish,  but  somewhat  lobed  organs,  just  below  and 
near  the  ventral  sucker.  The  uterine  tube  has  numerous 
branches  arranged  on  each  side  of  a  main  central  trunk,  in  the 
hinder  part  of  the  body.  The  ovaries  are  comparatively 
small  and  situated  on  each  side  of  the  middle  region  of  the 
body. 

Development. 

The  eggs  hatch  in  water,  after  several  weeks,  producing 
very  small,  nearly  round  embryos,  which  have  the  vibrating 
cilia  only  on  the  head  end,  which  is  a  little  smaller  than  the 
other  end.  They  are  not  such  lively  swimmers  as  the  em- 


PARASITES    OF   ANIMALS.  109 

bryos  of  the  common  fluke.  They  are  about  ¥^  to  -^  of  an 
inch  long,  and  ^-^^  of  an  inch  broad.  The  head  end  is  pro- 
vided with  a  dagger-like  boring  spine,  which  can  be  alternate- 
ly thrust  out  and  withdrawn.  It  is  supposed  that  these  em- 
bryos become  parasitic  in  fresh-water  snails,  for  a  time,  and 
undergo  transformations  like  those  described  under  the  pre- 
ceding species.  Their  effects  and  remedies  are  the  same  as 
for  the  common  fluke,  though  owing  to  their  small  size  they 
would  be  less  injurious,  unless  in  much  greater  numbers. 

The  Stomach-flukes  of  Cattle  (AmpTiistoma  conicum  Rud.  and 
A.  crumeniferum  Creplin). 

The  flukes  belonging  to  the  genus  Amphistoma,  which  in- 
cludes, besides  the  two  indicated,  A.  explanatum  from  the 
bile-ducts  of  cattle  and  A.  truncatum  from  the  cat,  have  a 
small,  rather  thick,  and  somewhat  conical  body,  the  mouth- 
sucker  being  at  the  small  end.  The  large  end  is  rounded  and 
bears  the  other  sucker,  which  is  always  much  larger,  near  the 
posterior  end.  The  stomach  and  reproductive  organs  are 
nearly  like  those  of  Distoma.  The  eggs  also  produce  ciliated 
embryos  in  the  water,  and  they  are  supposed  to  go  through 
similar  transformations.  I  do  not  know  that  either  of  them 
have  been  observed  in  sufficient  numbers  to  produce  serious 
diseases  in  cattle. 

ACANTHOCEPHALA. 

(Thorn-headed  worms. ) 
Echinorhynchm  gig  as  Goeze.  Figures  74,  75. 
This,  which  is  the  only  representative  of  the  order  hitherto 
found  in  our  domestic  mammals,  is  quite  frequent  in  the  intes- 
tine of  hogs.  It  may  at  once  be  known  by  the  peculiar  pro- 
boscis, which  bears  several  circles  of  small  but  sharp  hooks, 
which  are  arranged  alternately,  in  quincunx,  mostly  toward 
the  end  of  the  proboscis  (Figure  75).  These  worms  have  a 
long  roundish  body,  tapering  to  the  posterior  end.  The  skin 
is  generally  crossed  by  numerous  transverse  wrinkles,  but  is 
sometimes  smoothish.  The  color  is  whitish  or  a  little  bluish. 
The  males  grow  to  the  length  of  three  or  four  inches,  with  a 


110 


BOARD  OF  AGRICULTURE. 


diameter  of  one-eighth  to  one-fifth  of  an  inch.  The  females 
may  become  six  inches,  or  even  a  foot  in  length,  and  some- 
times one-quarter  of  an  inch  in  diameter,  though  generally 

Figure  74. 


smaller.     The  female  is  very  prolific,  producing  an  immense 
number  of  somewhat  oblong-oval  eggs. 

The  history  of  its  development  and  transformations  has 
not  yet  been  made  out.  There  can  be  little  or  no  doubt, 
however,  that  the  young  worms  are  parasitic  in  some  other 
animals, — most  likely  in  insects,  worms,  or  snails, — and  that 
the  hogs  get  them  by  devouring  the  embryos  included  in 
some  such  small  animals. 

Effects  and  Symptoms. 

This  is  the  commonest  and  most  injurious  intestinal  worm 
found  in  swine.     These  parasites  live  in  the  small  intestine, 
and  more  rarely  in  the  large  intestine.     They  usually  adhere 
to  the  lining,  or  mucus  membrane,  by  means          Figure  75. 
of  the  hooks  on  the  proboscis,  which  is  thrust 
into  the  substance  of  the  membrane.     Not 
unfrequently  they  perforate  the  walls  of  the 
intestine  and  stray  into  other  parts  of  the 
viscera,    producing   serious    disease.     Some- 
times the  intestine  of   a  hog  is   found  per- 
forated by  so  many  of  these  holes  that  it  can- 
not be  used  in  the  manufacture  of  sausages  ! 

In  severe  cases,  hogs  afflicted  with  this  parasite  are  weak 
in  the  loins,  and  have  the  membranes  in  the  corners  of  the 
eyes  swollen,  watery,  and  lighter  colored  than  usual.  The 
excrement  is  hardened  and  highly  colored,  and  the  animal 
often  keeps  up  a  continual  squealing  and  grunting,  especially 
in  the  morning.  Such  hogs  are  generally  cross  and  morose, 

Figure  74. — Echinorkynchus  gigas,  natural  size.    From  Cuvier. 
Figure  75. — Head  of  E.  gigas,  enlarged  showing  the  reticulated  vessels  in  the 
skin.    From  Curier. 


PARASITES   OF   ANIMALS.  Ill 

biting  and  snarling  at  its  companions,  but  is  usually  too  weak 
to  defend  himself,  if  attacked  in  return,  and  is  easily  thrown 
down.  Finally  the  weakness  increases  until  the  poor  crea- 
ture is  unable  to  walk  about,  or  to  stand.  This  parasite  will 
probably  yield  to  the  same  remedies  used  for  tape-worms,  or 
those  employed  against  the  common  round-worms  of  man  (As- 
caris  lumbricoides) ,  to  which,  therefore,  the  reader  should  refer. 

NEMATODES. 

(Round-worms  and  Thre  ad-worms  J) 
The  Flesh-worm  (Trichina  spiralis  Owen).  Figure  76. 
This  most  important  and  most  dangerous  of  all  human  para- 
sites, is  a  very  minute  round  worm,  which  in  the  larval  state 
lives  in  the  muscles  of  man,  swine,  dogs,  cats,  rats,  mice, 
rabbits,  Guinea-pigs,  and  many  other  animals,  and  in  the  ma- 
ture state  inhabits  the  intestines  of  the  same  animals.  The 
body  is  slender,  smooth,  and  round.  The  intestine  is  com- 
posed of  a  series  of  small,  bead-like  swellings,  separated  by 
constrictions.  The  male  is  much  smaller  than  the  female, 
when  mature  measuring  only  TV  of  an  inch  ;  its  body  is  filiform, 
pointed  at  the  head,  enlarged  at  the  opposite  end,  generally 
somewhat  bent  or  curved  upon  itself ;  the  head  is  very  small 
and  pointed,  unarmed,  but  with  a  minute  central  mouth  ;  the 
posterior  end  of  the  body  is  furnished  with  a  bilobed  ap- 
pendage, the  anal  opening  being  between  the  lobes  ;  the  penis 
is  a  single  spiculum,  cleft  above  so  as  to  have  a  V-shaped  out- 
line. The  female  is  stouter  than  the  male  and  longer,  meas- 
uring about  -J-  of  an  inch,  when  mature  ;  the  posterior  end  is 
bluntly  rounded ;  the  genital  orifice  is  at  about  a  fifth  of  the 
length  from  the  anterior  end  of  the  body.  They  are  viviparous 
and  the  uterus  occupies  most  of  the  body,  in  the  form  of  along 
and  wide  tube,  in  which  the  embryos  are  closely  packed.  The 
eggs  are  T^7o  of  an  inch  long.  The  young  Trichinae, like  young 
tape-worms,  occur  imbedded  in  the  muscles  of  the  hog  and 
various  other  animals,  and  man.  But  unlike  the  young  tape- 
worms or  "  measles,"  the  young  Trichince  are  so  small  as  to  be 
quite  invisible  to  the  eye,  and  millions  of  them  may  ex- 
ist in  the  flesh  of  a  pig  without  producing  any  unusual  appear- 
ance in  the  meat  sufficient  to  attract  the  attention  even  of  an 


112 


BOARD  OF  AGRICULTURE. 


expert,  unless  examined  with  a  powerful  microscope.  This  is 
one  reason  why  deaths  so  frequently  occur  from  eating  pork 
filled  with  this  parasite.  When  recently  introduced  into  pork 
or  human  flesh,  the  little  worms  are  free  and  coiled  up  among 
the  muscular  fibres,  but  after  four  or  five  weeks  they  become 
enclosed  in  minute,  whitish,  elongated,  oval  or  roundish  cysts 
or  capsules,  due  to  the  irritation  and  inflammation  that  they 
cause  by  feeding  and  moving  (Fig.  76).  After  a  year  or  more 
these  cysts  become  calcified  by  a  deposit  of  carbonate  of  lime 
in  the  membrane,  and  at  this  time  are  visible  to  the 
eye  as  minute  specks,  about  the  size  of  hemp-seed,  scattered 
through  the  muscles.  When  enclosed  in  the  cyst,  the  worms 
become  dormant,  and  though  they  may  live  for  years,  and 
even  some  weeks  after  the  death  of  their  host,  they  can  do  no 
further  harm  unless  swallowed  by  man  or  some  animal.  Each 
cyst  contains  a  little  slender  worm  about  one  twenty-fifth  or 
one  thirtieth  of  an  inch  long,  and  one  seven  hundredth  thick, 
coiled  up  in  two  or  three 

turns.    The  cysts  average  Ei£ure  76> 

about  one  eightieth  of  an 
inch  long  and  a  hundred 
and  thirtieth  thick. 

If  pork  or  other  flesh 
containing  these  worms, 
either  free  or  enclosed  in 
cysts,  be  eaten  by  man, 
they  become  liberated  in 
the  stomach,  and,  en- 
tering the  intestine  at- 
tach themselves  to  its  soft 
lining,  and  there,  sur- 
rounded with  abundant 
food,  they  grow  very  rap- 
idly and  become  mature, 
with  fully  developed  sex- 
ual organs,  in  two  days. 

Figure  76. — A  small  piece  of  human  muscle  containing  encysted  young  of 
Trichina  spircdis  Owen,  enlarged  forty-five  diameters.  From  Hearth  and  Home, 
after  Leuckart. 


PARASITES   OF    ANIMALS.  113 

The  females  are  larger  and  more  numerous  than  the  males, 
and  become  about  one-eighth  of  an  inch  long  when  full  grown. 
They  pair  as  soon  as  mature,  and  the  males  soon  die  ; 
but  the  females  begin  to  give  birth  to  living  young  in  five 
or  six  days  from  the  time  when  they  enter  the  stomach, 
and  they  live  long  enough  to  produce  a  brood  of  from  five  hun- 
dred to  one  thousand  young  worms  each.  As  one  ounce  of  pork 
sometimes  contains  a  quarter  of  a  million  or  more  of  the  worms, 
it  is  not  surprising  that  the  millions  of  adult  worms  and  their 
offspring,  sometimes  resulting  from  a  single  meal  of  raw 
pork,  should,  by  their  presence,  produce  great  irritation  and 
inflammation  of  the  intestine  and  violent  diarrhoea  and  vomit- 
ing, which  are  often  the  first  symptoms  in  severe  cases.  But 
the  young  worms,  almost  as  soon  as  born,  begin  to  eat  or 
force  their  way  through  the  membranes  of '  the  intestine  into 
the  minute  blood-vessels  and  other  organs,  thus  vastly  in- 
creasing the  irritation.  Entering  the  circulation  they 
are  carried  by  the  blood  to  the  heart,  thence  to  the  lungs, 
and  then  become  diffused  through  the  whole  system.  Accord- 
ing to  other  observers,  the  young  worms  force  their  way  di- 
rectly through  the  intestine  and  all  other  intervening  organs, 
until  they  finally  reach  a  suitable  habitation  in  the  voluntary 
muscles.  It  is,  however,  difficult  to  understand  how  they  can 
become  so  evenly  and  generally  distributed  through  the  whole 
muscular  system  as  they  often  are,  if  this  be  their  only  mode 
of  diffusing  themselves.  It  is,  therefore,  not  improbable  that 
they  migrate  by  both  these  methods,  part  entering  the  circu- 
lation and  part  going  directly  through  the  tissues,  while  in 
either  case,  if  they  find  themselves  in  an  unfavorable  locality, 
they  have  the  power  of  changing  their  position  while  still  in 
the  free  state.  According  to  Dr.  Leuckart,  they  travel  by  the 
way  of  the  intermuscular  connective  tissues,  and  are  found 
most  abundantly  in  the  groups  of  muscles  nearest  the  abdomi- 
nal cavity,  especially  in  those  that  are  smallest  and  have  the 
most  connective  tissue. 

Effects. 

Large  numbers  often  lodge  in  the  heart,  lungs,  and  various 
other  organs,  producing  great  irritation  and  various  danger- 
15 


114  BOARD   OP   AGRICULTURE. 

ous  symptoms,  but  the  majority  finally  reach  and  remain  in 
the  voluntary  muscles,  where  they  live  and  thrive  for  some 
weeks,  making  for  themselves  passages,  and  even  entering  and 
destroying  the  fibres  themselves.  All  these  operations  cause, 
of  course,  an  immense  amount  of  inflammation  and  irritation, 
if,  as  often  happens,  millions  of  these  flesh-worms  are  at  work 
at  the  same  time  in  all  parts  of  the  system  ;  and  it  is  no  won- 
der that  many  violent  symptoms  and  high  fever  result,  or  that 
there  should  be  intense  soreness  and  pain  or  paralysis  of  the 
muscles,  and  dropsical  swellings.  Death  in  severe  cases  may 
occur  at  any  time  from  the  fifth  to  the  fiftieth  day.  The  du- 
ration of  the  disease,  like  its  severity,  is  in  direct  proportion  to 
the  number  of  living  Trichinae  swallowed,  and  varies  from  two 
weeks  to  three  or  four  months.  Even  in  many  comparatively 
mild  cases,  the  sutfering  is  intense  and  the  recovery  slow  and 
tedious,  while  many  secondary  diseases,  like  pneumonia,etc.,are 
liable  to  ensue.  When  all  the  worms  have  become  lodged  in 
the  muscles  and  enclosed  in  cysts,  the  direct  symptoms  cease, 
and,  if  the  strength  of  the  patient  has  been  kept  up,  recovery 
is  probable.  Some  persons,  especially  females,  are  much  more 
severely  affected  than  others,  by  the  same  number  of  the  para- 
sites. 

Persons  in  robust  health  may  be  able  to  survive  the  attack 
of  half  a  million  or  more  of  these  flesh-worms  and  recover, 
but  there  is  a  limit  to  all  human  endurance,  and  the  numbers 
often  contained  in  the  muscles  of  animals  or  persons  who 
have  been  killed  by  them,  are  almost  incredible.  In  a  cat  fed 
with  trichinous  flesh  by  Leuckart,  they  were  so  numerous  that 
he  estimated  that  one  ounce  of  the  flesh  contained  at  least 
325,000  worms.  Microscopic  preparations,  not  much  larger 
than  a  pin's  head,  often  contain  from  ten  to  forty  worms,  and 
one  bit  of  muscle,  weighing  about  one-fifth  of  a  grain,  from  a 
child  that  died  on  the  seventy-ninth  day,  contained  fifty- 
eight.  Allowing  only  one  hundred  worms  to  a  grain  of  mus- 
cle, a  man  weighing  150  pounds  might  contain  over  forty 
millions  of  the  parasites,  and  the  length  of  the  muscular 
fibres  actively  inflamed  by  such  a  number,  if  placed  in  a  line, 
would  amount  to  more  than  120  miles. 


PARASITES   OF   ANIMALS.  115 

In  some  very  severe  cases  the  numbers  contained  in  human 
bodies  have  been  estimated,  by  reliable  authorities,  as 
high  as  forty  and  sixty  millions. 

The  cysts  containing  Trichince  were  first  observed  in  human 
muscles  in  1822,  but  the  worms  from  similar  cysts  were  first 
named  and  described  by  Owen,  in  1835,  but  were  only  regarded 
as  anatomical  curiosities  of  no  practical  importance,  until  1860, 
when  Zenker  proved  that  they  are  capable  of  producing  the 
severe  and  often  fatal  disease  now  well  known  under  the  name 
of  Trichiniasis,  but  which  had  been  previously  (as  it  often  is 
still)  confounded  with  typhoid  fever,  inflammatory  rheuma- 
tism or  rheumatic  fever,  poisoning,  and  various  other 
diseases. 

Symptoms  and  treatment  of  the  disease. 

The  disease  caused  by  this  parasite  has  three  more  or  less 
distinct  phases : 

First.  While  the  mature  worms  and  young  remain  in  the 
intestine,  and  while  passing  through  its  walls.  In  this  stage 
the  symptoms  are  derangement  and  inflammation  of  the  in- 
testine, often  resulting  in  severe  diarrhoea,  nausea  and  vomit- 
ing, swelling  and  pain,  and  sometimes  peritonitis,  due  to  the 
perforations  of  the  intestinal  walls.  These  symptoms  ensue 
in  two  or  three  days  after  swallowing  the  trichinous  flesh,  and 
may  last  a  fortnight  or  more.  Animals  experimented  upon  often 
die  in  this  stage.  Purgatives  and  anthelmintics  are  used  in 
this  stage  to  expel  the  mature  and  pregnant  females,  but  after 
three  or  four  weeks  have  passed  this  will  be  useless.  Castor- 
oil  and  calomel  have  been  used  with  success  for  this  purpose. 

Second.  While  the  young  worms  are  migrating  and  work- 
ing in  the  muscles,  a  variety  of  symptoms  are  developed, 
varying  in  different  persons,  and  depending,  also,  upon  the 
number  of  worms.  This  stage  commences  in  ten  to  fourteen 
days,  and  generally  lasts  four  or  five  weeks.  The  principal 
symptoms  are  lassitude  and  swelling  of  the  muscles,  with 
soreness,  or  intolerable  pains,  resembling  rheumatic  pains  but 
not  affecting  the  joints  ;  profuse  sweating  sometimes  occurs  ; 
the  pulse  is  very  rapid,  but  the  heat  of  the  body  is  usually 


116  BOARD   OF   AGRICULTURE . 

low,  often  never  exceeding  102°  Fahr. ;  the  face  frequently 
becomes  suddenly  and  greatly  swollen,  and  sometimes  the 
whole  body  is  affected  in  the  same  way.  In  certain  cases,  a 
peculiar  congestion  of  the  eyes  has  been  observed.  In  general, 
many  of  the  symptoms  in  this  stage  resemble  those  of  typhoid 
fever. 

In  very  severe  cases  the  patient  is  unable  to  use  the  mus- 
cles or  move  the  limbs  without  the  most  intense  agony,  and 
filially  is  obliged  to  lie  passively,  flat  upon  the  back,  with  the 
arms  and  legs  somewhat  bent,  in  the  position  that  gives  the 
least  pain ;  and  later  the  limbs  are  rigidly  stretched  out,  some- 
what apart,  the  body  stiff,  and  the  muscular  system  in  a  state 
of  more  or  less  complete  paralysis.  Children  generally  lie 
on  the  side,  with  the  body  bent  and  the  legs  drawn  up.  The 
jaws  are  sometimes  closed  as  in  lock-jaw.  The  breathing  is 
difficult,  shallow,  and  rapid.  The  lungs  are  often  affected, 
and  frequently,  also,  the  heart ;  and  many  secondary  diseases 
are  liable  to  ensue. 

The  most  that  can  be  done  in  this  stage  of  the  disease  by 
the  physician  relates  to  the  relief  of  special  symptoms  and 
secondary  diseases,  and  sustaining  the  strength  of  the  system 
until  nature  may  in  time  effect  a  cure.  Most  experimental 
animals  die  in  this  stage,  and  human  patients,  also,  frequently 
perish  even  during  the  early  part  of  this  period. 

Third.  In  case  the  patient  survives  the  two  first  stages,  the 
inflammation  gradually  ceases,  breathing  becomes  more 
natural,  and  recovery  generally  commences,  but  in  very  severe 
cases  the  muscles  and  other  organs  have  been  so  much  in- 
jured as  not  to  perform  their  proper  functions,  and  general  de- 
bility often  results,  ending  in  a  kind  of  consumption  that  finally 
proves  fatal.  In  many  cases  of  recovery,  lameness  lasts  for 
several  months.  In  many  cases,  however,  the  final  recovery 
is  complete  and  may  be  followed  by  robust  health,  although 
tens  of  thousands  of  living  worms  may  be  still  enclosed  in 
the  capsules  in  the  muscles. 

From  this  it  is  obvious  that  a  hog  may  be  fat  and  appear  in 
every  respect  healthy,  and  yet  his  flesh  may  contain  such  im- 
mense numbers  of  the  parasites  as  to  be  capable  of  killing  a 


PARASITES   OF   ANIMALS.  117 

hundred  or  more  persons,  should  they  eat  it  raw  or  but  slightly 

cooked. 

Oases  of  Trichiniasis. 

Since  1860  thousands  of  cases  have  been  observed  and  hun- 
dreds of  deaths  are  known  to  have  occurred,  especially  in 
Germany,  where  the  custom  of  eating  various  forms  of  raw 
or  imperfectly  cooked  pork  is  much  more  common  than  in 
this  country.  At  Hettstadt,  in  1863,  the  flesh  of  one  pig  in- 
fected one  hundred  and  thirty-five  persons,  of  whom  twenty 
died.  Several  other  similar  "  epidemics"  have  also  occurred 
in  the  same  country.  In  the  United  States,  many  sad  cases 
have  also  been  recorded,  as  the  following  in  stances  will  show: 

At  Marion,  Iowa,  May,  1866,  Mr.  Bemis  and  eight  mem- 
bers of  his  family  ate  rare -done  and  raw  ham,  and  were  im- 
mediately taken  sick.  Up  to  June  3d,  three  had  died,  and 
others  were  considered  critical.  A  post-mortem  examination 
showed  about  two  hundred  thousand  worms  to  a  cubic  inch  of 
muscle  in  one  of  those  who  died. 

AtDubuque,  Iowa,  according  to  Dr.  Asa  Horr,  two  families 
were  attacked.  In  one  five  persons  died  ;  in  the  other,  five 
or  six.  Through  him  we  also  learn  of  a  case  where  the 
mother  of  a  family  ate  of  the  interior,  rare-done  part  of  a 
ham  and  took  the  disease,  while  those  who  ate  the  outside 
escaped. 

At  Springfield,  Mass.,  February,  1867,  Mr.  Ransley  Hall 
and  family  ate  of  raw  ham,  and  all  seven  were  attacked  in 
various  degrees,  according  to  the  amount  eaten.  A  daughter, 
aged  seventeen,  died,  and  the  father  had  a  long  and  very 
dangerous  illness. 

At  Albany,  N.  Y.,  January,  1869,  two  boys  ate  of  raw  ham 
and  were  infected ;  the  rest  of  the  family  ate  of  the  same 
ham,  when  cooked,  and  escaped. 

At  Rome,  Oneida  County,  N.  Y.,  December,  1868,  Mr. 
John  Wilbrecht  and  family,  nine  persons  in  all,  ate  raw 
smoked  and  dried  sausages.  All  were  dangerously  sick,  and 
four  adults,  the  father,  son,  and  two  daughters  died  before 
January  15th.  Their  sausages  and  salt  pork  were  examined 
and  found  to  be  full  of  Trichina,  as  were  also  the  muscles  of 
those  who  died. 


118  BOARD   OF   AGRICULTURE. 

In  New  York  City,  January,  1869,  eight  cases  occurred  in 
a  boarding-house  in  Carlisle  Street,  from  eating  sausages. 
Two  of  the  victims  died  in  the  New  York  Hospital,  and  others 
were  dangerously  sick.  It  is  a  significant  fact  that  the  physi- 
cians in  two  hospitals  mistook  these  cases  at  first  for  typhoid 
fever,  and  only  discovered  the  mistake  after  one  death  had 
occurred. 

In  Bridgeport,  Conn.,  January  30th,  1870,  raw  smoked 
ham  was  eaten  by  five  persons.  Of  these  Mrs.  Koch  died  of 
acute  Trichiiiiasis,  February  15th  ;  Mrs.  Winter  died  February 
16th  ;  Mr.  Winter  died  March  1st ;  a  daughter  of  Mrs.  Koch, 
aged  two  and  a  half  years,  died  March  7th.  Mr.  Strasburg 
was  for  a  long  time  very  dangerously  ill,  and  was  left  in  a  very 
feeble  condition.  Another  person  who  ate  some  of  the  same 
ham  fried,  escaped  entirely.  Mr.  Winter  thought  himself  not 
seriously  ill  when  his  wife  died.  Some  portions  of  his  pec- 
toral muscles,  which  I  have  had  an  opportunity  to  examine, 
were  filled  with  Trichincs,  not  yet  encysted.  There  were 
perhaps  100,000  to  the  cubic  inch. 

Prevention. 

Experiments  have  fully  shown  that  nothing  less  than  the 
most  thorough  cooking,  so  prolonged  as  to  destroy  all  redness 
of  the  juices  even  in  the  interior  of  the  meat,  is  capable  of 
destroying  these  parasites  and  rendering  pork  a  safe  article 
of  food.  Cases,  some  of  them  fatal,  have  occurred  from  eat- 
ing ordinary  fried  sausages,  roast  pork,  and  pork  that  had 
boiled  two  hours.  But  the  majority  of  severe  and  fatal  cases 
have  happened  from  eating  smoked  ham,  raw  or  partly  cooked, 
and  various  kinds  of  smoked  and  dried  sausages,  which  are 
often  eaten  raw,  or  but  slightly  cooked. 

Therefore,  if  people  will  eat  pork  at  all,  they  should  make 
it  a  fixed  rule  never  to  eat  it  unless  thoroughly  cooked,  if 
they  would  avoid  one  of  the  most  painful  and  dangerous  dis- 
eases known. 

There  appears  to  be  no  certain  way  of  preventing  the 
disease  in  hogs,  for  it  is  probable  that  in  most  cases  they  get 
it  by  eating  rats  or  mice,  which  are  often  full  of  Trichince, 
but  it  is  quite  probable  that  they  may  often  be  infected  by 


PARASITES   OF   ANIMALS.  119 

eating  slaughter-house  offal.  It  is  possible,  also,  to  infect 
hogs  and  other  animals  by  means  of  the  mature  female 
Trichince  that  have  been  discharged  from  the  intestines  of 
men  or  animals,  before  all  the  young  worms  contained  in  their 
uteri  have  been  born.  Therefore  hogs  may  obtain  this,  as 
well  as  the  Iarva3  of  the  tape-worm  of  man  and  many  other 
parasites,  by  being  kept  in  places  where  they  have  access  to 
manure,  as  is  too  often  the  case.  Cats,  rats,  mice,  rabbits, 
Guinea-pigs,  young  dogs,  and  various  other  animals  may  be 
infected,  but  adult  dogs,  like  old  hogs,  are  not  nearly  so  likely 
to  become  infected  as  the  young.  Although  lambs,  calves, 
and  horses  may  be  infected  by  forcing  them  to  eat  trichinous 
meat,  it  is  probable  that  they  seldom  or  never  become  infected 
naturally. 

Trichocephalus  dispar  Rudolphi.     Figure  77. 
This  is  a  small  round-worm,  living  in  the  human  intestine, 
and  remarkable  for  its  long,  very  slender,  filiform  neck,  which 
Figure  77.       *s  about  two-thirds  of  the  entire  length.     The 
male  grows  to  the  length  of  one  inch  and  a 
half,  and  the  female  to  two  inches.     The  sur- 
face of  the  body  appears  smooth  to  the  naked 
eye,  but  when  magnified,  a  longitudinal  band  of 
minute,  wart-like  papillae  is  seen  on  one  side. 
The   male   has   the  posterior  end  of  the  body 
spirally  curved,  with  a  single  spicule,  which  is 
emitted  from  the  extremity  of  the  body,  and  is 
enclosed  in.  a  short,  tubular  sheath,  that  is  cov- 
ered with  minute  recurved  spinules.  The  female 
has  the  posterior  end  of  the  body  nearly  straight 
and  bluntly  pointed  (Figure  77).     The  genital 
orifice  is  situated  at  the  origin  of  the  neck.     The  eggs  are 
elliptical,  with  a  small  projection  at  each  end,  and  are  -&G  to 
?fa  of  an  inch  long.    They  are  discharged  from  the  human  in- 
testine before  the  contained  embryos  are  fully  developed.     If 
kept  in  water  for  six  months  or  more  they  hatch,  liberat- 
ing a  minute  embryo  3^  of  an  inch   long,   which    tapers 
from  behind  toward  the  head. 

Figure  7 '7. —Trichocephalus  dispar,'  a,  female,  natural  size ;  b,  posterior  end,  en- 
larged.   From  Guerin. 


120  BOARD  OF  AGRICULTURE. 

It  is  therefore  probable  that  they  are  taken  into  the 
human  system  in  impure  water.  In  some  regions  it  is  very 
common.  Davaine  estimates  that  one-half  of  the  inhabitants 
of  Paris  entertain  this  parasite.  Its  effects  are  not  well  made 
out,  but  it  does  not  seem  to  cause,  ordinarily,  any  marked  in- 
convenience. It  lives  in  the  coecum  and  small  intestine. 
TricJiocephalus  affinis  Rud. 

This  species  lives  in  the  coecum  of  cattle,  sheep,  deer,  and 
antelopes.  It  closely  resembles  the  preceding,  but  the  reck 
part  is  still  longer  and  more  slender.  The  posterior  end  of 
the  male  is  curved  in  a  close,  conical  spiral,  and  the  spicule, 
like  its  sheath,  is  much  longer,  being  equal  to  about  a  third  of 
the  length  of  the  body.  The  genital  orifice,of  the  female  is 
situated  at  the  summit  of  a  prominent,  hour-glass  shaped 
papilla,  which  is  obliquely  truncated  at  the  summit  and 
covered  with  minute  spinules,  like  those  of  the  spicule-sheath 
in  the  male.  The  eggs  are  similar  to  those  of  the  preceding 
species  and,  without  doubt,  develop  in  the  same  way.  It  is 
not  known  to  cause  any  serious  disease. 

Spiroptera  strongylina  Rud.,  from  the  Hog.     Figure  78. 

The  genus  Spiroptera  includes  numerous  species  of  small, 
whitish  or  reddish,  slender,  round  worms,  which  taper  some- 
what toward  the  anterior  end,  or  toward  both       Figure  78. 
ends.     The  head  is  small,  and  either  naked,  or 
with  small  papillae.     The  male  has  the  posterior 
end  curved  in  a  spiral,  with  membranous  expan- 
sions,    and     with    two    unequal    intromittent 
spicules.     In  the  female  the  posterior  end  of  the 
body   is  nearly  straight  and  conical,    and  the 
ovary  is  either  simple  or  double,  with  the  genital 
orifice  situated  at  one  side  of  the  body. 

The  8.  strongylina  has  a  smooth,  tapering  body,  with  a 
simple  head  and  mouth.  The  male  spicules  are  very  long, 
relatively  to  the  entire  length  of  the  body.  The  male  grows 
to  the  length  of  half  an  inch  or  more.  The  female  to  more 
than  three-fourths  of  an  inch.  It  lives  in  the  stomach  of  the 
hog,  but  ordinarily  does  not  produce  any  serious  disease. 

Figure  78. — Spiroptera  str any y Una ;  a,  male,  natural  size;   b,  spicnles  and  pos- 
terior end  of  the  body,  enlarged.    From  Guerin, 


PARASITES   OF   ANIMALS.  121 

Spiroptera  megastoma  Rudolphi,  of  the  Horse. 
This  is  a  small  species,  which  has  a  more  cylindrical  body, 
tapering  a  little  toward  each  end.  The  head  is  separated  by 
a  slight  constriction  and  bears  four  lobes.  The  mouth  is 
large.  The  male  becomes  rather  more  than  a  quarter  of  an 
inch  long,  and  the  female  nearly  half  an  inch.  It  lives  in 
the  stomach  and  oesophagus  of  the  horse  and  produces 
tubercles,  or  hard  tumors,  of  considerable  size,  most  frequent- 
ly situated  near  the  pylorus.  These  contain  many  cavities, 
connected  together  and  filled  with  purulent  matter,  in  which 
there  are  numerous  specimens  of  the  parasite.  The  tumors 
are  sometimes  one  and  a  half  inches  in  diameter,  and  there 
are  at  times  several  in  the  same  stomach. 

Spiroptera  sanguinolenta  Rudolphi,  of  the  Dog. 
This  is  a  larger,  reddish  species,  which  produces  similar 
tumors  in  the  oesophagus  and  stomach  of  the  dog.  This 
species  usually  grows  to  the  length  of  one  and  a  half  to  three 
inches,  but  it  has  been  found  ten  inches  long,  living  in  the 
cavities  of  the  ventricles  of  the  heart  of  dogs  at  Shanghai, 
China,  where  it  appears  to  be  very  common.  Its  complete 
history  is  unknown,  and  therefore  little  can  be  said  about  the 
special  means  of  prevention,  or  cure.  It  often  produces  death. 

Pin-worm  of    the  Horse    (Oxyuris  curvula   Rudolphi). 
Figure  79. 

This  is  a  small,  whitish  worm,  quite  commonly  found  in 
the  coecum  and  colon  of  the  horse  and  ass.  The  female  is 
about  one  inch  and  a  half  to  two  inches  long,  when  mature. 
The  male  is  far  more  rare  and  but  one-third  to  two-thirds  of 
an  inch  long.  The  body  is  fusiform,  tapering  to  a  slender 
tail,  thicker  in  front,  with  the  anterior  end  more  or  less 
pointed.  The  mouth  is  situated  at  the  end,  and  usually  has 
the  form  of  a  small,  round  pore,  but  is  provided  with  three  or 
four  small  retractile  papillae,  which  can  be  protruded.  The 
buccal  cavity  contains  a  peculiar  apparatus  of  folds  and  tooth- 
like  processes ;  the  oesophagus  is  long  and  muscular,  round 
externally,  but  with  a  three-cornered  cavity  ;  it  is  separated 
from  the  round,  gizzard-like  stomach  by  a  constriction,  and 
16 


122  BOARD  OP  AGRICULTURE. 

then  a  second  constriction  separates  the  stomach  or  gizzard 
from  another  somewhat  enlarged  cavity,  which  tapers  grad 
ually  into  the  slender  intestine.  The  anal  orifice  is  near  the 
posterior  end  of  the  body,  and  in  the  male  also  gives  exit  to 
the  intromittent  organ,  which  is  a  single,  sharp,  grooved 
ticuluna^  with  a  very  small  accessory  one.  The  female 

•*^ 


orifice  is  situated  near  the  anterior  third  of  the  body.  This, 
like  the  other  species  of  Oxyuris^  produces  eggs  having  firm 
shells.  These  probably  hatch  in  water,  and  the  embryos  may 
thus  be  swallowed  in  drinking.  The  intestines  of  these  para- 
"sites  are  generally  filled  with  vegetable  matters  derived  from 
the  food  of  the  animals  in  which  they  live,  and  the  structure 
of  the  digestive  organ  seems  to  be  adapted  to  vegetable  food. 
For  this  reason  it  is  probable  that  they  ordinarily  cause  little 
or  no  inconvenience  to  the  horses  that  they  inhabit. 

The  Pin-worm  of  Man  (Oxyuris  vermicularis  Bremser). 

This  is  a  much  smaller  species  than  the  preceding,  but  is 
similar  inform.  It  is  very  common,  often  in  great  numbers,  in 
children,  and  occurs  also  in  adults,  especially  in  aged  and 
debilitated  persons,  and  inhabits  chiefly  the  lower  part  of  the 
rectum  and  the  vicinity  of  the  anus. 

The  male  is  about  one-eighth  of  an  inch  long,  with  the  tail 
curved  in  a  spiral  form,  terminating  in  a  very  short  point. 
The  female  is  about  four-tenths  of  an  inch  long  and  one- 
fiftieth  in  diameter,  with  the  posterior  part  of  the  body  taper- 
ing to  a  very  slender  tail. 

The  digestive  system  and  structure  of  the  mouth  is  similar 
to  that  of  the  preceding  species.  But  the  head  sometimes 
shows  inflated  lateral  lobes. 

Reproduction. 

This  species  is  very  prolific ;   each  female  produces  thou- 

Eigure  79. — Oxyuris  curvula,  female,  twice  natural  size.     From  Guerin. 


PARASITES   OF  ANIMALS.  123 

sands  of  eggs,  in  which  the  embryos  are  considerably  de- 
veloped before  they  are  laid.  The  embryos  enclosed  within 
the  eggs  are  shaped  somewhat  like  tad-poles,  the  slender  tail 
being  bent  up  against  the  lower  side  of  the  body,  which  faces 
the  flattened  side  of  the  egg.  The  body  is  broad  and  well 
fills  the  egg.  The  full  history  of  the  development  of  the  eggs 
is  not  yet  known.  It  is  probable,  however,  that  a  portion  of 
the  eggs  imbedded  in  the  mucus  membrane  of  the  intestine 
hatch  in  that  situation,  remaining  thus  in  the  same  person. 
But  it  is  also  probable  that  the  eggs  that  are  discharged  will 
hatch  in  water,  and  that  persons  become  infested  by  swallow- 
ing the  embryos  with  their  food  and  drink. 

Symptoms. 

The  most  marked  symptom  of  these  parasites  is  an  intoler- 
able itching  in  and  about  the  anal  orifice,  which  is  generally 
worst  in  the  evening  or  during  the  night,  when  the  worms  are 
migrating  or  changing  their  localities.  This  is  usually  accom- 
panied by  sensations  of  heat  and  inflammation.  Not  unfre- 
quently,  by  irritation  of  the  adjacent  nerves,  they  cause 
similar  sensations  in  the  genital  and  urinary  organs,  which 
sometimes  become  very  distressing.  They  sometimes  even 
migrate  into  the  genital  passages  of  female  children,  causing 
great  irritation  and  very  serious  symptoms.  By  the  irritation 
of  the  sexual  organs,  in  both  sexes,  various  unfortunate  sec- 
ondary diseases  and  bad  habits  not  unfrequently  result, 
especially  if  they  occur  at  the  period  of  early  puberty.  Other 
symptoms  caused  by  the  irritation  of  the  nervous  system,  are 
restlessness,  general  nervousness,  involuntary  twitchings, 
itching  of  the  nose,  chorea,  convulsions,  and  sometimes 
epileptiform  seizures. 

Remedies. 

The  various  medicines  ordinarily  used  as  anthelmintics,  or 
vermifuges,  will  often  bring  away  large  numbers  of  these 
worms.  Of  these  the  etherial  extract  of  male  fern  is  probably 
the  best,  but  santonine  and  panna  have  been  used  with  good 
results.  Ordinarily  they  can  be  treated  more  easily  and 
effectively  by  means  of  injections  of  cold,  or  nearly  cold, 


124  BOARD  OP  AGRICULTURE. 

water,  to  which  may  be  added  a  small  amount  of  salt,  oil  of 
anise-seed,  or  assafoetida.  Sometimes  decoctions  of  quassia, 
worm-wood,  or  southern-wood  {Artemisia  abrotanum)  are 
used  for  this  purpose,  with  good  results.  To  these  a  portion 
of  olive-oil  may  be  added.  But  any  remedy  that  may  be  em- 
ployed must  be  repeated  as  often  as  once  every  three  or  four 
days  for  at  least  three  weeks,  in  order  to  destroy  the  young 
ones  as  fast  as  they  develop.  An  application  of  mercurial 
ointment  to  the  parts  about  the  anus  is  recommended  to  pre- 
vent the  migrations  of  the  parasites  and  the  uncomfortable 
itching  sensations  that  they  thus  produce. 

The   common   Hound-worm   of   Man    (Ascaris   lumbricoides 

Linn.). 

This  species  is  well  known  as  a  parasite  of  the  human  in- 
testine, especially  in  children,  though  often  found  in  persons 
of  all  ages.  The  round-worm  of  cattle  is  generally  regarded 
as  the  same  species. 

These  worms  are  round  and  smooth,  tapering  to  both  ends, 
with  a  tough,  elastic  skin.  The  mouth  is  situated  at  the  more 
pointed  end,  and  is  provided  with  three  prominent  papillae,  or 
fleshy  lobes.  The  male  grows  to  the  length  of  six  inches, 
and  has  the  posterior  end  curved  and  provided  with  two 
slender  spicules.  The  female  is  much  larger,  sometimes  be- 
coming twelve  or  fourteen  inches  long  and  one-fourth  of  an 
inch  in  diameter ;  the  female  genital  orifice  is  in  advance  of 
the  middle  of  the  body. 

Development. 

The  females  produce  great  numbers  of  minute  eggs,  which 
are  provided  with  thick,  rough  .shells.  The  eggs  are  dis- 
charged and  pass  from  the  human  intestine  before  the 
development  of  the  embryos  commences.  If  kept 
in  water  the  embryos  go  on  developing  slowly  and 
gradually,  the  whole  process  requiring  from  six  months 
to  nearly  a  year.  The  fully  developed  embryos  are 
round  and  slender,  about  T£o  of  an  inch  long,  with 
an  obtuse  head  and  an  acute  tail.  They  have  not  been  ob- 
served to  quit  the  eggs  of  their  own  accord,  but  may  live  for 
at  least  a  year  within  the  egg-shell,  after  they  attain  their  full 


PARASITES    OP    ANIMALS^  125 

size.  It  is  probable  that  such  eggs,  containing  embryos, 
when  swallowed  in  the  water  that  we  drink,  will  be  hatched 
in  our  stomachs  by  the  action  of  the  gastric  juice,  and  that 
the  young  worms  thus  reach  their  destined  abode.  It  is 
possible,  however,  that  under  the  proper  circumstances  the 
eggs  will  hatch  in  the  water,  and  that  the  free  swimming  em- 
bryos may  be  swallpwed  in  the  same  way.  This  part  of  their 
history  still  remains  uncertain. 

Symptoms. 

The  presence  of  one  or  two  of  these  parasites  in  the  human 
intestine  does  not  ordinarily  cause  any  marked  effects  or 
noticeable  symptoms.  But  when  they  occur  in  persons  of 
delicate  health,  and  when  in  great  numbers,  as  sometimes 
happens,  they  may  cause  great  disturbance  of  the  natural 
functions  of  the  digestive  system,  and  induce  various  serious 
consequences.  Cases  have  occurred  in  which  from  100  to 
500  of  these  worms  have  passed  from  one  child.  They  live 
chiefly  in  the  small  intestine,  but  sometimes  enter  the  stomach 
and  may  even  be  expelled  by  vomiting.  In  some  instances 
they  have  been  known  to  perforate  the  walls  of  the  intestine 
and  enter  the  abdominal  cavity,  and  thus  even  to  get  into  the 
other  organs,  including  the  lungs,  pleura,  gall-bladder,  etc. 
In  such  cases  death  often  results. 

Their  presence  in  the  stomach  and  intestine  causes  colic 
and  shooting  pains,  often  accompanied  by  nausea,  vomiting, 
dyspepsia,  itching  of  the  nose,  and  diarrhoea.  Owing  to  the 
irritation  of  the  nervous  system  they  may  cause  restlessness, 
convulsive  twitchings,  especially  during  sleep,  and  various 
mental  disturbances.  In  some  cases,  serious  convulsions, 
epilepsy,  and  insanity  have  been  caused  by  them,  and  have 
been  cured  at  once  by  expulsion  of  the  worms. 

Remedies. 

The  most  reliable  remedy  appears  to  be  santonine,  but  this 
is  a  powerful  preparation,  and  must  be  used  with  caution. 
For  children  the  dose  is  one  to  three  grains,  in  the  form  of 
powder,  which  does  best  if  taken  in  castor- oil  or.  honey, 
though  it  may  be  sprinkled  over  a  piece  of  bread  and  butter. 


126  BOARD   OF   AGRICULTURE. 

For  an  adult  the  dose  is  four  or  five  grains,  twice  a  day,  on 
every  second  day,  for  a  week,  the  quantity  to  be  diminished  if 
the  medicine  causes  ill  effects,  such  as  spasms,  tenesmus,  etc. 
It  often  causes  temporary  perversion  of  vision,  things  appear- 
ing of  unnatural  colors,  etc.,  but  this  effect  soon  passes  away. 

The  root  of  male  fern  (see  page  191),  given  in  powder,  in 
connection  with  purgative  medicines,  is  also  recommended. 

As  means  of  prevention,  the  use  of  impure  water  should  be 
avoided.  And  if  water  from  streams  and  ponds  must  be 
used  for  drinking,  as  in  most  large  cities,  it  should  be 
thoroughly  filtered  through  powdered  charcoal. 

The  Round-worm  of  the  Horse  (Ascaris  megalocephala 
Cloquet) . 

This  species  inhabits  the  intestine  of  the  horse,  ass,  and 
mule,  and  is  quite  common.  It  closely  resembles  the  preced- 
ing species  in  form  and  general  appearance,  but  grows  to  a 
larger  size,  the  male  becoming  ten  inches  long,  and  the  female 
twelve  inches  or  more.  The  mouth  is  surrounded  by  three 
large,  rounded,  very  prominent  lobes  or  papilla.  In  the  male 
the  tail  is  provided  with  wing-like  folds  along  the  sides  ;  in 
the  female  it  is  conical,  terminating  in  a  point,  the  female 
genital  opening  being  situated  in  the  anterior  fourth  of  the 
body. 

This  species  likewise  produces  vast  numbers  of  eggs,  which 
develop  embryos  externally  to  the  body,  in  water.  Dr.  Cob- 
bold  states  that  he  has  reared  free,  active  embryos  from  these 
eggs  by  keeping  them  five  months  in  water.  The  horses, 
most  probably,  swallow  these  embryos  in  the  water  that  they 
drink. 

These  parasites,  when  numerous,  will  no  doubt  produce 
effects  analogous  to  those  caused  in  the  human  body  by  the 
preceding  species,  and  the  remedies  will  be  similar. 

The  Round-worm  of  the  Cat  (Ascaris  mystaxRndolphi). 

Although  very  common  in  the  cat,  this  parasite  is  of  inter- 
est chiefly  on  account  of  its  occasional  occurrence  in  the 
human  intestine. 

It  may  be  easily  distinguished  by  the  presence  of  peculiar 


PARASITES    OF    ANIMALS.  127 

wing-like  membranous  expansions  on  each  side  of  the  head 
or  anterior  end  of  the  body.  The  male  grows  to  the  length 
of  two  and  one-half  inches ;  the  female  sometimes  becomes 
four  inches  long  and  one-twelfth  in  diameter. 

This  worm  probably  propagates  its  kind  in  a  manner  similar 
to  that  of  the  two  preceding  species,  and  no  doubt  gains  ad- 
mittance to  the  human  intestine,  as  well  as  to  that  of  the  cat, 
by  the  medium  of  impure  water  and  unclean  vegetable  food. 

Its  effects  and  remedies  are  the  same  as  those  of  the  com- 
mon round-worm. 

The  Round-worm  of  the  Hog  (Ascaris  suilla  Dujardin). 

This  very  closely  resembles  the  Ascarislumbricoides  of  man, 
and  probably  has  nearly  the  same  habits.  It  differs  chiefly  in 
the  structure  of  the  reproductive  organs.  The  male  spicules 
are  not  so  sharp,  and  the  tubes  of  the  uterus  are  much  longer. 
The  eggs  are  smaller.  It  appears  to  be  less  common  than 
the  Echinorhynchus  gigas  in  the  intestine  of  hogs,  and  prob- 
ably produces  less  injurious  effects. 

STEONGYLUS. 

The  genus  Strongylus  includes  slender,  filiform  worms, 
mostly  of  small  size,  and  often  reddish  in  color.  Several  of 
them  live  in  the  windpipe  and  bronchial  tubes  of  various 
animals,  including  sheep,  deer,  cattle,  pigs,  etc.,  and  when 
numerous  may  occasion  the  death  of  the  animals  that  they 
infest,  by  suffocation. 

The  body  generally  tapers  toward  the  head,  and  sometimes 
in  both  directions.  The  mouth  is  small,  situated  at  the  end 
of  the  small  head,  which  is  either  simple  or  with  lateral  ex- 
pansions. It  is  sometimes  surrounded  by  small  papilla,  but  is 
often  simple,  and  either  round  or  triangular,  but  not  enclosed 
by  a  hard  or  chitinous  organ,  as  in  Sclerostoma,  etc.  The 
oasophagus  is  enlarged,  club-shaped,  and  muscular. 

The  male  has  the  posterior  end  of  the  body  provided  with 
an  expanded,  often  lobed  pouch,  or  bursa,  for  adhering  to  the 
female  during  copulation.  The  spicule  is  slender  and  filiform, 
enclosed  in  a  sheath.  In  the  female  the  posterior  end  is 


128  BOARD    OF   AGRICULTURE. 

conical  or  pointed,  and  the  genital  orifice  is  placed  in  advance 
of  the  middle  of  the  body,  or  more  rarely  toward  the  pos- 
terior end. 

The    Strongylus   of    Sheep    {Strongylus  filaria   Rud.). 
Figure  80. 

The  present  species  is  whitish,  very  long  and  slender.    Th 
head  is  obtuse  and  without  appendages,  the  mouth  surrounded 
by  three  small  papillae.     The  caudal    pouch  of        Figure  so. 
the  male  is  entire,  with  ten  rays  (Figure   80). 
The  male  is  about  two  and  a  half  inches  long, 
and  the  female  three  and  a  half,  though  gener- 
ally not  more  than  two  or  three  inches  long,  the 
interior  of  the  body  of  the  female  is  mostly  oc- 
cupied by  two  long  convoluted  uterine  tubes, 
containing  eggs  in  which  the  embryos  are  in  all 
stages    of    development.      These    open   at   an 
orifice  situated  at  about  one-third  of  the  length 
of  the  body  from  the  head. 

Habits. 

This  species  lives  in  the  lungs,  air-passages, 
and  bronchial  tubes  of  sheep  and  other  rumi- 
nants. They  often  occur,  singly  or  several  to- 
gether, in  cavities  in  the  substance  of  the  lungs, 
producing  great  inflammation  and  destruction 
of  the  tissue,  which  often  results  in  the  death  of 
great  numbers  of  lambs,  and  greatly  injures  the 
health  of  old  sheep,  even  if  it  does  not  actually 
kill  them.  In  this  way  many  thousands  of 
lambs  are  annually  lost  in  certain  districts  in 
England.  In  this  country  we  have  far  less  in- 
formation concerning  the  extent  of  its  ravages, 
but  have  no  reason  to  suppose  that  it  is  less 
common  than  in  Europe,  in  localities  that  are  favorable  for  its 
development.  Sheep  infested  by  this  parasite  continually 
cough  up  the  eggs  and  embryos  of  the  worms,  and  either  dis- 
charge them  directly  from  the  nose  or  mouth,  or  swallow  them 


Figure  80. — Strongylus  filar ia,  male,  enlarged.     From  Thudichura. 


PARASITES   OF    ANIMALS.  129 

and  thus  pass  them  with  the  faeces.  In  either  case  they  will 
often  adhere  to  grass  *nd  other  herbage,  and  may  thus  be 
swallowed  by  other  sheep  or  lambs,  fed  in  the  same  pastures, 
and  pass  directly  into  the  windpipe,  or  else  do  so  when  the 
cud  is  raised  for  mastication.  Therefore  lambs  should  never 
be  put  into  fields  or  pastures  where  diseased  animals  have 
been  kept,  but  such  infected  lands  should  be  tilled,  or  at  least 
left  at  rest  for  several  months.  As  soon  as  an  animal  gives 
any  indication  of  the  presence  of  the  parasites  by  the 
peculiar  cough,  it  should  be  separated  from  the  rest  of  the 
flock  for  treatment ;  or  else  immediately  killed  and  the  para- 
sites should  be  effectively  destroyed,  and  not  thrown  on  the 
ground  as  harmless,  for  all  these  worms  are  remarkably 
tenacious  of  life,  and  often  may  even  be  dried  up  completely 
for  months,  and  then  revive  when  moistened. 

Remedies. 

When  these  parasites  are  once  lodged  in  numbers  in  the 
substance  of  the  lungs,  there  is  probably  no  reliable  remedy 
whatever.  When  merely  in  the  windpipe  and  bronchial  tubes, 
expectorant  medicines  that  will  produce  a  copious  secretion 
of  mucus  may  be  useful.  It  might  be  possible  to  remove 
them  by  a  surgical  operation,  opening  the  windpipe  from  'the 
exterior,  but  this  would  require  surgical  skill  and  would  not 
pay,  perhaps,  except  as  a  last  resort  for  valuable  animals. 

The    Strongylus  of    Cattle  and  Horses  (Strongylus  micrurus 

Mehlis). 

This  species  closely  resembles  the  preceding.  The  male 
grows  to  the  length  of  about  one  inch  and  a  half ;  and  the 
female  to  three  inches  or  a  little  more.  The  body  is  very 
slender  with  a  simple,  blunt  head.  The  bursa  of  the  male 
has  five  rays.  The  female  genital  orifice  is  near  the  middle 
of  the  body.  It  is  said  to  be  viviparous. 

The  habits  of  this  species  are  nearly  the  same  as  those  of 
the  last,  except  that  this  inhabits  the  air-passages  of  cattle, 
horses,  asses,  and  mules,  instead  of  sheep.  It  is  much  more 
liable,  like  the  former,  to  infest  young  animals  than  adults. 
Calves  less  than  a  year  old  are  particularly  liable  to  be  in- 
17 


130  BOARD   OF  AGRICULTURE. 

vaded,  and  those  that  are  once  attacked  seldom  or  never  re- 
cover. The  same  remarks,  concerning  the  means  of  preven- 
tion, made  under  the  preceding  species,  will  apply  equally  to 
this.  If  neglected,  these  parasites  increase  with  great 
rapidity,  and  thus  the  disease  that  they  cause  appears  like  an 
epidemic,  in  certain  localities  destroying  hundreds  or  thou- 
sands of  animals,  while  adjacent  farms  may  be  entirely  free 
from  it. 

The  Strongylus  of  the  Hog  (Strongylus  parodoxus  Mehlis). 

This  is  a  slender,  whitish  or  brownish  worm,  with  a  small, 
simple  head.  The  mouth  has  three  small  papillae.  The 
oesophagus  is  long  and  muscular.  The  anus  is  situated  some- 
what in  advance  of  the  posterior  end  of  the  body  at  the  sum- 
mit of  a  small  papilla.  The  male  becomes  half  an  inch  or 
more  in  length,  and  has  the  caudal  bursa  bilobed,  each  lobe 
with  five  rays,  the  lateral  ones  divided.  The  female  grows  to 
the  length  of  about  an  inch  and  a  half,  but  is  usually  about 
an  inch  long  ;  the  tail  is  terminated  by  a  point,  turned  to  one 
side  ;  the  genital  opening  is  near  the  posterior  end  and  a  little 
prominent.  This  species  is  viAdparous.  It  inhabits  the  wind- 
pipe, bronchial  tubes,  and  lungs  of  swine.  Its  history  and 
the  effects  it  produces  are  nearly  the  same  as  those  of  the 
Strongylus  filar  ia. 

The   Strongylus  of    the  Intestine   of    the   Hog   (Strongylus 
dentatus  Rud.). 

This  is  a  slender  filiform  species,  about  half  an  inch  long, 
which  lives  in  the  small  intestine,  coecum,  and  colon  of  hogs. 
The  head  is  obtuse  and  surrounded  by  six  acute  papillae.  The 
oesophagus  is  short  and  thick,  muscular.  In  the  male  the 
tail  is  truncated  and  provided  with  an  oblique  bursa,  formed 
of  a  single  piece,  strengthened  by  three  subdivided  rays  ; 
there  are  two  slender  spicules.  The  tail  of  the  female  is 
elongated  and  slender,  ending  in  a  fine  point ;  the  genital 
opening  is  near  the  posterior  end. 

The  effects  of  this  species  and  its  history  are  little  known. 


PARASITES   OF   ANIMALS.  131 

The  Strongylus  of  the  Intestine  of  Sheep  (  Strongylus  contortus 

Rud.). 

This  is  a  filiform  species,  tapering  to  both  ends,  but  more 
slender  toward  the  head,  which  is  provided  with  two  semi- 
elliptical,  wing-like  appendages ;  the  mouth  with  three  small 
papillse.  The  male  is  about  three-fourths  of  an  inch  long, 
with  a  bilobed  bursa,  each  lobe  with  about  eight  rays :  the 
sheath  of  the  male  spicule  is  very  long.  The  female  sometimes 
becomes  four  inches  long. 

It  is  not  uncommon  in  the  small  intestine  of  sheep,  but  its 
history  is  very  imperfectly  known.  When  abundant  it  may, 
without  doubt,  cause  serious  trouble. 

Strongylus  filicollis  Rudolphi . 

This  species  also  inhabits  the  small  intestine  of  sheep.  The 
body  is  very  slender  and  whitish  or  reddish.  The  head  has 
two,  very  small,  lateral,  wing-like  appendages.  The  male 
bursa  is  bilobed,  each  lobe  with  six  rays.  It  is  from  a  third 
to  four-fifths  of  an  inch  long. 

Strongylus  radiatus  Rudolphi. 

This  worm  lives  in  the  small  intestine  and  colon  of  cattle 
and  several  other  ruminants.  The  head  is  simple  ;  the  mouth 
naked.  The  male  is  about  half  an  inch  long,  with  a  bilobed 
caudal  bursa,  the  lobes  many  rayed.  The  female  is  about 
three-quarters  of  an  inch  long  ;  the  genital  opening  is  near 
the  tail. 

Its  complete  history  is  unknown. 

The  Kidney-worm  (Euslrongylus  gig  as  Diesing).     Figure  81. 

This  is  the  largest  of  all  the  Nematode  worms,  the  females 
sometimes  becoming  three  feet  long  and  half  an  inch  in 
diameter,  though  usually  much  less.  The  body  is  smooth, 
cylindrical,  tapering  somewhat  to  each  end,  and  more  or  less 
deeply  tinged  with  red.  The  head  is  simple,  obtuse.  The 
mouth  is  terminal  and  surrounded  by  six  rounded,  chitinous 
papillse.  The  male  becomes  ten  to  twelve  inches  long  and 
one-fourth  of  an  inch  in  diameter ;  the  caudal  bursa  is  cup- 
shaped,  circular  and  entire,  without  rays  ;  the  male  spicule  or 


132 


BOARD   OP   AGRICULTURE. 


penis  is  very  slender.  The  female  has  a  nearly  straight, 
obtuse  tail ;  the  anus  is  triangular,  near  the  end ;  the  genital 
orifice  is  anterior,  near  the  mouth  ;  the  ovaries  and  oviducts 
are  simple,  but  long  and  convoluted.  The  intestine  is  large 
and  blackish,  with  thin  walls,  and  quite  simple,  running 
directly  from  one  end  of  the  body  to  the  other,  and  is  attached 
to  the  sides  of  the  body,  along  its  whole  length,  by  fibres. 

Habits. 

This  formidable  parasite  lives  in  the  kidneys  of  man  and 
various  animals.     It  has  been  found  in  the  dog,  horse,  cattle, 
hog,  wolf,  \veasles,  mink,  otter,  seal, glutton,  raccoon, and  coati. 
In  this  country  it  has  been  found  quite  frequently  in  the  kid- 
Figure  si. 


neys  of  the  mink.  It  has  been  found  very  rarely  in  the  blad- 
der, in  the  abdominal  cavity,  and,  it  is  said,  in  the  heart.  In 
man  it  is  very  rare.  When  lodged  in  the  kidney  it  gradually, 
but  completely,  destroys  the  substance  of  the  organ,  which 
becomes  filled  with  purulent  and  bloody  matter,  upon  which 
the  worm  feeds,  while  the  walls  often  become  hardened  with 
calcareous  deposits.  The  effects  and  symptoms  are  the  same 
as  in  other  acute  diseases  or  abscesses  in  one  of  the  kidneys. 
The  only  positive  evidence  of  the  presence  of  the  worm  would 
be  the  discovery  of  the  eggs  in  the  urine.  It  is  probable  that 
no  remedy  can  be  applied  when  the  parasite  is  once  lodged  in 
the  kidney. 

The  history  of  this  worm  is  not  fully  known.  According 
to  Leuckart,  a  slender  worm  found  coiled  up  in  cysts  in 
the  muscles  and  peritoneum  of  fishes  is  the  young  or  larva  of 
some  species  of  Eustrongylus.  The  larval  form  referred  to 

Figure  81. — Eustrongylus gigas,  male,  less  than  natural  size;    a,  spiculum   and 
bursa ;  6,  anus  of  female,  enlarged.     From  Guerin. 


PARASITES  OF  ANIMALS.  133 

is  the  Filaria  cystica  Rudolplii,  originally  found  in  a  Brazilian 
fish  (^SymbrancTius  lalicaudus).  It  is,  therefore,  probable  that 
the  eggs  or  young  embryos  of  E.  gigas  are  swallowed  by 
fishes,  and  in  their  bodies  develop  into  the  larval  form  and  be- 
come encysted,  and  if  then  swallowed  by  some  mammal, 
migrate  into  its  kidneys  to  become  sexually  mature.  The 
frequency  of  these  parasites  in  those  animals  that  feed  chiefly 
on  fish,  such  as  the  otter,  mink,  and  seal,  renders  this  view 
very  probable. 

The    Crape-worm  of     Chickens,    etc.,    (Syngamus    trachealis 

Siebold).     Figure  82. 

This  parasite  lives  in  the  windpipe  and  bronchial  tubes  of 
chickens,  turkeys,  pheasants,  partridges,  crows,  wood-peckers, 
and   many  other  birds.     In  young  chickens  and  turkeys  it 
Figure  82.  often  proves  very  destructive,  by  filling  up 

the  air  passages,  and  thus  quickly  killing 
whole  flocks.     In   some   parts   of  this 
country  at  least  three-quarters  of  all  the 
young  chickens  and  turkeys  are  some- 
times destroyed  by  this  parasite.     The 
\l    \\     1!  /S       worms  are  reddish  in  color  and  have  a 
I       \KwJl     H       smo°th  skin,  but  spiral  depressions  run 
I  rm       around   the  body,  giving  it   a   twisted 

I  iH     1       appearance.     The   reproductive   organs 

show  through  the  skin,  as  slender, 
whitish,  convoluted  tubes.  The  males 
and  females  are  almost  invariably  found  united  firmly  to- 
gether, as  shown  in  the  figures,  the  integument  of  the  male 
soon  becoming  organically  united  to  that  of  the  female,  so 
that  the  copulation  is  permanent  or  for  life.  The  females  are 
very  much  larger  than  the  males,  becoming  about  three- 
quarters  of  an  inch  in  length,  and  one:sixteenth  of  an  inch 
in  diameter.  The  anterior  end,  in  both  sexes,  suddenly  ex- 
pands into  a  trumpet-shaped,  concave  disk,  in  the  middle  of 
which  the  mouth  is  situated,  surrounded  by  six  small  chitinous 
lobes  ;  the  posterior  portion  of  the  body  of  the  female  is  more 

Figure  82. — Syngamus  trachealis  Siebold  ;  a,  male  and  female  united,  natural 
size ;  6,  anterior  part  of  female,  enlarged ;  c,  male,  enlarged.    From  Cobbold. 


134  BOARD   OP   AGRICULTURE. 

or  less  bent  and  folded,  and  suddenly  narrows  at  the  end, 
terminating  in  a  small  point.  The  genital  orifice  is  near  the 
anterior  fourth  of  the  body,  where  the  caudal  bursa  of  the 
male  is  attached  and  conceals  it.  The  male  is  only  one-eighth 
or  one-seventh  of  an  inch  long  and  very  slender  ;  the  caudal 
bursa  is  simple,  sucker-like,  with  an  entire  margin,  strength- 
ened by  about  ten  rays  ;  the  penis  consists  of  two  very  small, 
cylindrical  spicules,  about  225  of  an  inch  long.  The  eggs  are 
oval,  about  250  of  an  inch  long.  The  embryos  develop  while 
the  eggs  are  still  in  the  oviducts  and  uterine  tubes,  and  the 
eggs  or  young  probably  escape  by  a  rupture  of  the  integument 
of  the  body  of  the  female. 

The  history  of  the  young  worms,  after  they  are  expelled 
from  the  windpipes  of  the  birds,  is  not  yet  known,  however. 
Possibly  they  may  enter  the  bodies  of  insects  to  pass  their 
larval  state,  but  it  is  more  probable  that  they  bury  themselves 
in  the  surface  of  the  soil  or  other  moist  places,  and  are  thus 
picked  up  directly  by  the  birds  and  gain  admittance  to  the 
windpipe  by  their  own  active  motions. 

Symptoms. 

The  disease  commonly  known  as  "  the  gapes "  is  caused 
solely  by  the  presence  of  numbers  of  these  worms  in  the  wind- 
pipe, which  thus  becomes  so  filled  up  as  to  render  respiration 
difficult,  and  if  in  considerable  numbers,  by  their  growth  the 
obstruction  becomes  complete,  and  death  results  from  suffoca- 
tion. Young  chickens,  thus  attacked,  seldom  recover  without 
special  treatment  for  the  removal  of  the  worms.  Chickens 
only  three  or  four  days  old  often  show  symptoms  of  the  dis- 
ease by  opening  wide  their  mouth  and  gasping  for  breath,  and 
attempting  to  swallow.  They  also  frequently  sneeze.  As  the 
disease  grows  worse  these  symptoms  become  more  marked; 
they  continually  gasp  and  struggle  for  breath,  grow  weak  and 
dispirited,  and  finally 'droop  and  die.  In  fatal  cases,  one  or 
two  dozen  of  these  worms  are  often  found  in  the  windpipe, 
completely  filling  it  up. 

Remedies. 

The  worms  may  be  removed  by  a  feather  from  which  the 
web  has  been  stripped,  except  a  small  portion  near  the  tip. 


PARASITES   OP   ANIMALS.  135 

This  may  be  moistened  with  oil,  salt-water,  or  a  weak  solution 
of  carbolic  acid,  and' introduced  into  the  windpipe,  when  if  it 
be  twisted  round  once  or  twice  and  removed,  it  will  usually 
bring  away  several  of  the  worms.  The  operation  should  be 
repeated  at  intervals  until  all  the  worms  are  destroyed.  All 
worms  removed  in  this  or  any  other  way  should  be  carefully 
destroyed,  preferably  by  fire,  for  the  embryos  are  extremely 
tenacious  of  life,  and  if  left  upon  the  ground  are  likely  to 
spread  the  disease.  For  the  same  reason,  those  birds  that  are 
infected  should  be  separated  from  the  healthy  ones,  and  poultry 
should  never  be  allowed  to  run  in  the  same  yards  or  grounds, 
or  be  kept  in  the  same  houses  where  infected  ones  have  previ- 
ously been  kept,  unless  the  premises- have  first  been  thor- 
oughly sprinkled  with  a  strong  solution  of  carbolic  acid  or 
petroleum-water,  to  destroy  those  old  worms  or  the  eggs  and 
embryos  that  may  have  been  discharged  from  the  sick  ones. 
The  vessels  from  which  they  feed  should  be  frequently  and 
thoroughly  cleansed,  and  they  should  be  supplied  with  pure 
water,  frequently  renewed. 

In  extreme  cases,  the  worms  may  be  safely  removed  by  a 
surgical  operation  ;  but  this  requires  some  skill.  This  is  done 
by  first  carefully  securing  the  bird,  or  still  better  by  adminis- 
tering a  few  drops  of  chloroform,  placed  upon  cotton  and 
held  to  the  nostrils.  The  skin  of  the  neck  is  then  to  be  di- 
vided with  a  very  sharp  knife,  and  the  windpipe  opened  by  a 
longitudinal  slit  about  a  quarter  of  an  inch  long.  The  worms 
may  then  be  removed  by  a  pair  of  small  forceps  or  other  suit- 
able instrument.  ,  The  incision  in  the  skin  may  be  closed  by 
one  or  two  stitches,  and  the  wound  will  generally  heal  in  a 
few  days.  By  this  operation  an  almost  instantaneous  cure 
may  be  effected,  even  when  the  disease  has  progressed  nearly 
to  the  point  of  suffocation  ;  but  in  unskilful  hands  it  is  not 
likely  to  be  so  successful  as  the  remedies  already  described. 

The  Sclerostoma  of  the  Horse  (Sclerostoma  equinum  Dujardin, 
or  S.  armatum  Davaine).   Figure  83. 

This  is  a  small,  slender,  cylindrical  worm,  reddish  or  brown- 
ish in  color,  which  lives  in  the  intestines,  and  in  peculiar 
enlargements  of  the  arteries  of  horses,  asses,  and  mules.  The 


136  BOARD   OP   AGRICULTURE. 

head  is  round,  nearly  globular,  supported  by  a  cliitinous  bulb 
or  capsule,  truncated  at  the  end,  where  the  large,  round 
mouth  is  situated.  The  mouth  is  surrounded  by  one  to  sev- 
eral circles  of  fine  denticles,  or  converging  hooks.  The  oesc- 
phagus  is  muscular  and  thick,  club-shaped,  separated  from 
the  intestine  by  a  strong  constriction. 

The  male  is  an  inch  or  an  inch  and  a  quarter  long,  with  a 
large,  membranous,  caudal  bursa,  divided  into  two  lateral 
lobes,  which  are  strengthened  by  numerous  rays ;  there  arc 
two  long  and  slender  spicules.  The  female  grows  to  the  length 
of  one  and  a  half  to  two  inches,  with  a  long,  tapering,  caudal 
portion,  the  anus  not  terminal ;  the  ovaries  long  and  con- 
voluted around  the  intestines,  and  showing  through  the  integu- 
ments ;  the  uterine  tubes  are  double  and  contain  great  num- 
bers of  eggs,  in  which  embryos  are  developed. 

Habits. 

This  parasite  is  very  common  in  the  horse,  generally  living 
attached  by  the  hooks  of  its  head  to  the  lining  membrane  of 
the  intestine,  particularly  in  the  coecum  and  colon,  but  some- 
times in  the  small  intestine  and  duodenum,  and  even  in  the 
pancreas.  At  the  points  where  it  adheres  it  Figure  83. 
causes  small,  dark-colored,  raised  spots.  They 
sometimes  occur  in  vast  numbers  in  the  large 
intestine,  completely  covering  the  surface ; 
the  number  sometimes  amounting,  it  is  said, 
to  a  million  or  more.  Ordinarily,  however, 
these  parasites,  when  lodged  in  the  intestines, 
do  not  appear  to  produce  any  marked  dis- 
ease or  notable  symptoms,  although  when  in 
great  numbers,  there  can  be  no  doubt  but 
that  they  must  cause  some  inflammation  and 
pain.  More  serious  results,  sometimes  prov- 
ing fatal,  happen  when  the  worms  enter  the 
blood-vessels.  They  produce  large  aneurisms  or  dilations  of 
the  arteries,  chiefly  in  the  anterior  mesenteric  artery,  but 

Figure  83. — Sclerostoma  equinum,  female,  natural  size ;  and  anterior  portion  en- 
larged ;  a,  mouth ;  b,  circle  of  hooks ;  c,  oesophagus ;  d,  intestine ;  e,  reproductive 
organs.  From  Cuvier. 


PARASITES    OP    ANIMALS.  137 

also  in  the  arteries  of  the  colon,  coecum,  small  intestine,  and 
liver,  as  well  as  in  the  posterior  mesenteric  and  renal  arteries, 
and  others  adjacent  to  the  intestine.  These  tumors  are  gen- 
erally fusiform,  and  as  large  as  a  man's  finger ;  but  they  are 
sometimes  globular,  and  may  become  as  large  as  a  man's 
head.  The  middle  membrane  of  the  artery  in  these  dilations 
becomes  enormously  thickened,  sometimes  being  twelve  times 
as  thick  as  in  the  healthy  artery.  In  old  tumors  various  hard 
or  calcareous  deposits  often  take  place  in  the  thickened  walls 
or  in  the  inner  membrane ;  and  in  such  cases,  the  walls  being 
weakened,  are  liable  to  be  ruptured  by  some  unusual  exertion 
of  the  animal,  when  death  results  almost  instantly.  In  the 
interior  of  the  aneurism  there  is  generally  a  deposit  of  fibrin, 
firmly  adherent  to  the  inner  surface.  In  this  and  in  the  dif- 
ferent layers  of  the  walls  the  worms  are  found,  —  sometimes 
only  a  few,  but  frequently  large  numbers.  This  disease  is 
very  prevalent  among  old  horses.  In  France,  as  many  as 
ninety-six  out  of  one  hundred  have  been  found  affected  with 
the  disease. 

I  am  not  aware  that  any  remedies  have  ever  proved  useful. 
Generally  it  would  be  impossible  to  detect  the  disease  during 
life,  unless  the  tumors  became  very  large. 

Sclerostoma  pinguicola  Yerrill. 

On  two  occasions  I  have  received  specimens  of  a  rather 
large  parasitic  worm,  which  lives  in  the  fat  of  hogs.  In  the 
first  case,  five  specimens  were  obtained,  at  New  Haven,  by 
Dr.  M.  C.  White,  from  the  fatty  portion  of  a  spare-rib  ;  in  the 
second  instance,  at  Middletown,  Conn.,  Dr.  N.  Cressy  found 
large  numbers  of  the  worms  in  the  fat  about  the  kidneys  of  a 
young  Suffolk  pig,  brought  from  New  Jersey.  Un- 
fortunately, none  of  these  specimens  are  in  so  good  a  state 
.of  preservation  as  to  enable  me  to  determine  with  certainty 
all  the  points  of  their  structure.  Those  which  I  owe  to  the 
kindness  of  Dr.  White,  had  been  mounted  in  glycerine  as 
microscopic  objects  and  pressed  out  flat,  before  they  came 
into  my  possession,  and  the  tissues  were  thus  injured  and 
the  organs  deranged.  Those  from  Dr.  Cressy,  were  both 
pressed  flat  and  dried.  Yet  by  careful  masceration,  and 
with  much  labor,  I  believe  that  most  of  the  important  char- 
18 


138 


BOARD    OF   AGRICULTURE. 


acters  have  been  made  out.  The  body  is  rather  robust,  es- 
pecially in  the  female,  and  tapers  to  both  ends ;  the  color  is 
yellowish  white,  and  the  integument  is  seen  to  be  finely 
striated  transversely,  when  considerably  magnified.  The 
head  is  smaller  than  the  body,  truncated  at  Figure  83  a. 
the  end ;  the  mouth  is  terminal,  roundish,  or 
somewhat  angular,  surrounded  by  the  thick- 
ened rim  of  the  chitinous  capsule,  or  pharynx. 
This  chitinous  ring  rises  at  intervals  into  four 
to  six  denticles,  or  very  small  teeth,  which 
correspond  to  thickened  longitudinal,  chitin- 
ous bands,  that  strengthen  the  pharynx,  and 
give  a  slightly  angular  form  to  the  mouth. 
The  pharynx  itself  is  small,  short,  and  rather 
squarish,  when  seen  in  profile,  and  has  three 
or  four  small,  conical  teeth  at  the  bottom. 
The  oesophagus  is  thick,  club-shaped,  and  very  muscular. 

The  male  is  1.12  of  an  inch  long,  and  about  .05  of 
an  inch  in  diameter  ;  the  tail  ends  in  a  small  blunt  lobe, 
united  with  two  small,  entire,  membranous  expansions, 
one  on  each  side,  forming  a  small  bursa,  which  is 
strengthened  by  several  short  rays,  the  exact  number  of 
which  could  not  be  determined  in  my  specimens  ;  there 
are  two  long,  slender  spicules.  The  females  are  1.25 
to  two  inches  in  length,  and,  as  flattened  between  glass, 
they  are  .10  to  .13  of  an  inch  in  breadth.  The  posterior 
end  suddenly  and  obliquely  narrows  to  a  small  conical 
point,  which  is  turned  to  one  side.  The  anal  opening  is  close 
to  the  end,  and  the  genital  orifice  appears  to  be  adjacent  to 
it.  The  oviducts  are  long,  voluminous,  much  convoluted, 
and  unite  in  a  large  and  capacious  uterus,  which  fills  most 
of  the  cavity  of  the  body  near  the  posterior  end.  The  uterus 
and  oviducts  are  both  filled,  in  the  larger  specimens,  with  im- 
mense numbers  of  small  oval  eggs. 

It  is  probable  that  this  parasite  is  by  no  means  uncommon. 

Pentastoma  tcenioides  Rudolphi.     Figure  84. 
This  parasite  is  not  a  true  worm,  but  is  now  generally  re- 
Figure  83  a. — Sclerostoma  pinguicola ;  a,  male,  natural  size  ;  b,  posterior  end,  en- 
larged; c,  female,  natural  si/e;  d,  head,  enlarged.    Original. 


PARASITES  OF  ANIMALS. 


139 


garded  as  belonging  to  the  Acarians,  with  the  true  mites.  In 
the  adult  state  it  inhabits  the  nostrils  and  frontal  sinuses  of 
dogs  and  wolves,  and  more  rarely,  of  horses  and  sheep.  The 
larvse,  formerly  described  under  the  name  of  Pentastoma  den- 
ticulatum,  lives  in,  cysts  on  the  outside,  or  in  the  outer  por- 
tion, of  the  liver  of  sheep,  deer,  antelopes, .  peccary,  porcu- 
pine, Guinea-pig,  rabbit,  hare,  rat,  and  cat ;  and  some- 
times invades  the  human  body  in  the  same  way.  It  has  also 
been  found  free  in  the  visceral  cavity  of  the  body. 

In  the  mature  state  (Figure  84)  the  body  is  long,  lance- 
shaped,  tapering  behind,  flattened  below,  and  divided  into 
about  ninety  segments  by  transverse  lines.  The  segments 
next  to  the  head  bear  two  pairs  of  small,  but  strong  and 
Figure  84.  sharp,  retractile  claws,  which  represent  the  true 
legs  of  ordinary  mites.  The  mouth  is  broad- 
oval,  and  provided  with  a  hard  chitinous  lip. 
The  segments  behind  the  head  are  perforated 
by  small  openings,  regarded  by  many  as 
spiracles,  or  breathing  pores.  The  adult  is 
smooth,  but  the  larvae  are  covered  with  many 
rows  of  small,  sharp  spines.  The  male  is 
only  .07  to  .08  of  an  inch  in  length,  but 
the  female  becomes  three  or  four  inches  long, 
and  half  an  inch  wide.  The  female  genital 
opening  is  in  the  tail,  that  of  the  male,  in  the 
middle  of  the  front  part  of  the  abdomen.  They 
are  oviparous,  and  the  young  undergo  a  com- 
plete and  remarkable  metamorphosis. 
The  adults  live  in  the  nasal  cavities  of  dogs,  and 
produce  an  irritation  of  the  delicate  membranes,  which 
causes  a  flow  of  mucus,  often  accompanied  by  sneez- 
ing. The  eggs  discharged  with  the  mucus  .may  ad- 
here to  vegetables  or  fruit,  or  get  into  drinking- 
water,  and  in  these  ways  gain  admittance  to  the  stomach  of 
man,  or  other  animals.  In  the  stomach  they  hatch  into  mi- 
nute embryos,  furnished  with  a  boring  apparatus  and  two  pairs 
of  double  claws.  They  bore  their  way  through  the  intestines 
and  lodge  in  the  liver  or  other  parts,  and  soon  become  dor- 


140  BOARD    OF    AGRICULTURE. 

mant  and  enclosed  in  cysts,  in  which  they  pass  a  sort  of 
pupa  state.  During  this  period  of  their  life,  the  skin  is  cast 
several  times,  and  the  appearance  changes  at  each  moult,  un- 
til they  attain  the  next  period  of  their  life,  when  they 
again  become  active  ;  this  is  the  state  described  as  Petastoma 
denticlatum.  These  larvae  are  long-oval,  broadest  anterior- 
ly, and  covered  with  numerous  rows  of  transverse  tooth-like 
spinules.  They  have  two  pairs  of  sharp,  curved  claws,  which 
are  situated  near  the  mouth  and  placed  obliquely,  diverging 
from  the  median  line  of  the  body,  and  directed  downward. 
Each  claw  has  a  sort  of  hood  or  capsule,  into  which  it  can  be 
retracted.  If  dogs  feed  on  the  liver  or  other  viscera  of  animals 
containing  these  larvae,  they  come  in  contact  with,  and  man- 
age to  enter  the  nose,  working  their  way  up  by  means  of  the 
motions  of  the  body,  aided  by  their  spines  and  claws.  In 
this  situation  they  gradually  become  mature. 

In  the  human  body  the  larval  form  is  quite  frequent,  es- 
pecially in  some  parts  of  Europe  ;  but  there  is  little  known 
concerning  the  effects  that  it  produces.  When  in  small  num- 
bers, it  probably  causes  very  little  disturbance,  but  if  in  large 
numbers,  in  the  liver  and  lungs,  it  would  no  doubt  produce 
serious  disease,  as  does  another  species  (P.  constrictuin) , 
which  is  very  common  in  Egypt,  living  in  the  same  way  en- 
cysted in  the  liver  and  lungs.  The  latter,  when  in  consider- 
able numbers,  frequently  proves  fatal. 

As  a  means  of  prevention,  dogs  that  show  symptoms  of 
the  parasites  in  the  nose,  should  be  treated  to  a  solution  of 
carbolic  acid,  thrown  up  the  nostrils  by  a  small  syringe. 
Feeding  dogs  with  the  offal  of  slaughter  houses,  or  with  un- 
cooked livers,  etc.,  should  be  avoided,  both  on  account  of  this 
and  the  other  dangerous  parasites  that  they  get  in  this  way, 
(see  Tcenia  echinococcm,  p.  202,  T.  marginata,  p.  192,  T. 
ccenurus,  p.  196,  and  Trichina  spiralis,  p.  222).  Too  much 
familiarity,  especially  of  children,  with  dogs  is  always  liable 
to  result  in  the  transfer  of  these  and  other  parasites  to  the 
human  body. 


ERRATA. 

In  making  up  the  author's  copies,  and  repaging,  several  errors  have  been  intro- 
duced, which  the  reader  should  correct : — 
Page  3  third  line  of  foot  notes,  for  Corydalus  cornutas,  read  Corydalis  cornutus. 

"     6,  line  19,  for  orceps,  read  forceps. 

"     8,     "    31,  for  pair,  read  pairs. 

"12,    "    13,  for  labium,  read  labrum. 

"   13,  figure  18  is  inverted. 

"  4*7,     "    17..  for  page  89,  read  page  16. 

"  48,    "    10,  for  page  109,  read  page  38. 

"  49,    "    31,  for  page  109,  read  page  38. 

''  60,    "    10,  for  nemarum,  read  venarum. 

"  61,    "    23,  for  page  101,  read  page  30. 

"  85,    "      5,  for  page  191,  read  page  80. 

"  100,  "  34.  It  should  be  stated  that  Dr.  Cobbold,  in  1860,  fed  dogs  with  a 
small  cysticercus,  from  the  liver  of  rabbits,  but  distinct  from 
"  G.  pisiformis"  and  obtained  specimens  of  Tcenia  cucwnerina, 
which  he  thought  were  developed  from  them. 

"  110,    "    30,  for  "  such  hogs  are,"  read  such  a  hog  is. 

"126,    <l      6,  for  page  191,  read  page  80. 

"140,  lines  32  and  33,  for  page  202,  read  91;  for  192,  read  81;  for  196,  read 
85;  for  222,  read  111. 


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